Viability of government funded broiler production : lessons from Northern KwaZulu Natal, South Africa
- Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
Evaluation of spatial distribution and health risk of pesticide residues in the environmental matrices of buffalo river estuary and their removal using nanosponges and modified cyclodextrins
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Evaluation of water and sanitation challenges in informal settlements: a case study of Duncan Village, East London, South Africa
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Design and development of mobile-based e-Marketing application for communal farmers in Eastern Cape. South Africa.
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
Investigation into response of wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Molecular characterization of integrons and their associated gene cassettes in multidrug-resistant enterobacteriaceae isolates from environmental sources and the exploration of antibiotic combination against some resistant strains
- Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Authors: Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Date: 2023
- Subjects: Enterobacteriaceae , Molecular microbiology , Enterobacteria
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27809 , vital:69942
- Description: Globally, the increasing rate of antimicrobial resistance against our currently available drugs has been a serious public concern. Due to the selective nature of antibiotics, bacteria are expected to develop resistance against them over time, but the current scourge of antimicrobial resistance is aggravated by factors other than the expected evolutionary trend. The use and overuse of antibiotics in clinical and agricultural contexts have led to the fast rise of multidrug-resistant MDR microorganisms. A scenario that necessitates an upsurge in the clinical failures observed with our current drug arsenals is expected to rise if left unchecked. One of the significant drivers implicated in the spread of antimicrobial resistance genes is the integrons. These are mobile genetic elements found on pathogenicity islands, transposons, and plasmids, easing their distribution among various bacteria. They are considered efficient gene expression systems that naturally capture, integrate gene cassettes GCs and immediately express the captured antimicrobial resistance genes on the GCs due to the inherent promoters on their structures. Integrons have been known to confer resistance against most classes of antibiotics. These include all known β-lactams, chloramphenicol, trimethoprim, erythromycin, aminoglycosides, quinolones, streptothricin, lincomycin, rifampicin, fosfomycin, and antiseptics of the quaternary ammonium compound family. They have been detected in bacterial populations under direct or indirect antibiotic pressure in clinical, agricultural, and environmental contexts. The emergence of MDR in Enterobacteriaceae is a critical public health issue that has attracted the World Health Organization WHO, which classified them as one of the critical priority pathogens urgently requiring new antibiotics. The resistance phenomenon has proven most of the current antibiotics ineffective, further compounded by the slow pace of the discovery of new antibiotics, necessitating the hunt for new, practical remedies. One of such is the exploration of synergy among existing antibiotics. Two medications combined have a higher impact, thereby allowing current antibiotics to be salvaged for use in treating MDR bacteria, even if the bacteria are resistant against one or both antibiotics separately. Hence, this research focused on the occurrence and prevalence of multidrug resistance and the characterization of integrons and their associated gene cassettes in members of Enterobacteriaceae, including Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Escherichia coli, and Citrobacter spp. recovered from animal droppings, rivers, and effluents of hospital and wastewater treatment plants in Eastern Cape Province, South Africa. The inhibitory effect of combining two drugs belonging to different antibiotic classes to obtain a possible potentiating effect against some multidrug-resistant Enterobacteriaceae isolates harbouring integrons were examined and studied. The isolates were identified using the conventional molecular Polymerase Chain Reaction with specific primers. The antimicrobial resistance profile and the production of Extended-spectrum and metallo β-lactamase were detected using disk diffusion technique DDT, double-disk synergy test DDST, and ethylenediaminetetraacetic acid EDTA tests, respectively. The PCR-based screening method, DNA sequencing analyses, and restriction fragment length polymorphism RFLP were used to characterize the integrons and their associated GCs. Furthermore, Enterobacterial Repetitive Intergenic Consensus ERIC PCR determined the genotypic relationships between some specific species. The various antibiotics' minimum inhibitory concentration MIC was determined using the broth microdilution, while the checkerboard method was used to determine the fractional inhibitory concentration indices FICIs. The time-kill assays TKAs were further used to confirm the synergism observed from the checkerboard assays. Most of the isolates were resistant against most antibiotics tested and were considered MDR. The least resistance was observed against imipenem, a carbapenem, one of the drugs of last resort. Also present were the ESBL and MBL producers, with a few isolates co-producing the enzymes. A high prevalence of integrons was observed in the isolates, with class 1 integrons being the most frequently detected. Some isolates co-harboured the intI1 and intI2 genes and were classified as class1 plus 2 integrons. Although Citrobacter spp. had the least number of isolates among the Enterobacteriaceae studied, it harboured the most diverse gene cassette arrays. The various gene cassette arrays were identified as follows: For Klebsiella spp. Aac 6 Ib, aadA1 dfrA1, and dfrA1 sat2; for Citrobacter spp., dfrA5 aac3 Ib, aac6 ib, aadA1dfrA1 aadA1, aadA1-dfrA1, aadA5 dfrA17, and dfrA21-aac3-Ib; for E. coli dfrA21- aac-3-Ib, dfrA5-aac-3-Ib, aadA1 dfrA1, and aadA5 dfrA17 and for E. cloacae aadA1 dfrA1, dfrA7 dfrA21 dfrA5 aac 3 Ib, and dfrA1 sat2. The GC array dfrA1 sat2 was the only array detected in class 2 integrons which are analogous to that found in Tn7, dfrA1-sat2-aadA1, with the deletion of the last GC aadA1. These detected GCs confer resistance against aminoglycosides, including streptomycin and spectinomycin, and trimethoprim, further increasing the resistance spectrum of the bacterial species harbouring them. The detection of integrons and their associated GC and the presence of these β-lactamases is also associated with coresistance against other classes of antibiotics by bacterial species harbouring them, further limiting treatment options. The checkerboard assays combining antibiotics against these drug-resistant integron harbouring Enterobacteriaceae revealed that 26.3 percent 10 over 38 of the interactions were categorized as synergistic, while 73.7 percent 28 over 38 were indifferent. None of the combinations was antagonistic. The TKAs revealed all the synergistic interactions as bactericidal. Therefore, the combinations of gentamicin with tetracycline, ciprofloxacin, and ceftazidime against Multidrug-resistant MDR Klebsiella pneumoniae; tetracycline-ceftazidime combination against MDR Escherichia coli, colistin combinations with ceftazidime and gentamicin, and tetracycline-gentamicin combinations against MDR Citrobacter freundii may be future therapeutic alternatives. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Date: 2023
- Subjects: Enterobacteriaceae , Molecular microbiology , Enterobacteria
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27809 , vital:69942
- Description: Globally, the increasing rate of antimicrobial resistance against our currently available drugs has been a serious public concern. Due to the selective nature of antibiotics, bacteria are expected to develop resistance against them over time, but the current scourge of antimicrobial resistance is aggravated by factors other than the expected evolutionary trend. The use and overuse of antibiotics in clinical and agricultural contexts have led to the fast rise of multidrug-resistant MDR microorganisms. A scenario that necessitates an upsurge in the clinical failures observed with our current drug arsenals is expected to rise if left unchecked. One of the significant drivers implicated in the spread of antimicrobial resistance genes is the integrons. These are mobile genetic elements found on pathogenicity islands, transposons, and plasmids, easing their distribution among various bacteria. They are considered efficient gene expression systems that naturally capture, integrate gene cassettes GCs and immediately express the captured antimicrobial resistance genes on the GCs due to the inherent promoters on their structures. Integrons have been known to confer resistance against most classes of antibiotics. These include all known β-lactams, chloramphenicol, trimethoprim, erythromycin, aminoglycosides, quinolones, streptothricin, lincomycin, rifampicin, fosfomycin, and antiseptics of the quaternary ammonium compound family. They have been detected in bacterial populations under direct or indirect antibiotic pressure in clinical, agricultural, and environmental contexts. The emergence of MDR in Enterobacteriaceae is a critical public health issue that has attracted the World Health Organization WHO, which classified them as one of the critical priority pathogens urgently requiring new antibiotics. The resistance phenomenon has proven most of the current antibiotics ineffective, further compounded by the slow pace of the discovery of new antibiotics, necessitating the hunt for new, practical remedies. One of such is the exploration of synergy among existing antibiotics. Two medications combined have a higher impact, thereby allowing current antibiotics to be salvaged for use in treating MDR bacteria, even if the bacteria are resistant against one or both antibiotics separately. Hence, this research focused on the occurrence and prevalence of multidrug resistance and the characterization of integrons and their associated gene cassettes in members of Enterobacteriaceae, including Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Escherichia coli, and Citrobacter spp. recovered from animal droppings, rivers, and effluents of hospital and wastewater treatment plants in Eastern Cape Province, South Africa. The inhibitory effect of combining two drugs belonging to different antibiotic classes to obtain a possible potentiating effect against some multidrug-resistant Enterobacteriaceae isolates harbouring integrons were examined and studied. The isolates were identified using the conventional molecular Polymerase Chain Reaction with specific primers. The antimicrobial resistance profile and the production of Extended-spectrum and metallo β-lactamase were detected using disk diffusion technique DDT, double-disk synergy test DDST, and ethylenediaminetetraacetic acid EDTA tests, respectively. The PCR-based screening method, DNA sequencing analyses, and restriction fragment length polymorphism RFLP were used to characterize the integrons and their associated GCs. Furthermore, Enterobacterial Repetitive Intergenic Consensus ERIC PCR determined the genotypic relationships between some specific species. The various antibiotics' minimum inhibitory concentration MIC was determined using the broth microdilution, while the checkerboard method was used to determine the fractional inhibitory concentration indices FICIs. The time-kill assays TKAs were further used to confirm the synergism observed from the checkerboard assays. Most of the isolates were resistant against most antibiotics tested and were considered MDR. The least resistance was observed against imipenem, a carbapenem, one of the drugs of last resort. Also present were the ESBL and MBL producers, with a few isolates co-producing the enzymes. A high prevalence of integrons was observed in the isolates, with class 1 integrons being the most frequently detected. Some isolates co-harboured the intI1 and intI2 genes and were classified as class1 plus 2 integrons. Although Citrobacter spp. had the least number of isolates among the Enterobacteriaceae studied, it harboured the most diverse gene cassette arrays. The various gene cassette arrays were identified as follows: For Klebsiella spp. Aac 6 Ib, aadA1 dfrA1, and dfrA1 sat2; for Citrobacter spp., dfrA5 aac3 Ib, aac6 ib, aadA1dfrA1 aadA1, aadA1-dfrA1, aadA5 dfrA17, and dfrA21-aac3-Ib; for E. coli dfrA21- aac-3-Ib, dfrA5-aac-3-Ib, aadA1 dfrA1, and aadA5 dfrA17 and for E. cloacae aadA1 dfrA1, dfrA7 dfrA21 dfrA5 aac 3 Ib, and dfrA1 sat2. The GC array dfrA1 sat2 was the only array detected in class 2 integrons which are analogous to that found in Tn7, dfrA1-sat2-aadA1, with the deletion of the last GC aadA1. These detected GCs confer resistance against aminoglycosides, including streptomycin and spectinomycin, and trimethoprim, further increasing the resistance spectrum of the bacterial species harbouring them. The detection of integrons and their associated GC and the presence of these β-lactamases is also associated with coresistance against other classes of antibiotics by bacterial species harbouring them, further limiting treatment options. The checkerboard assays combining antibiotics against these drug-resistant integron harbouring Enterobacteriaceae revealed that 26.3 percent 10 over 38 of the interactions were categorized as synergistic, while 73.7 percent 28 over 38 were indifferent. None of the combinations was antagonistic. The TKAs revealed all the synergistic interactions as bactericidal. Therefore, the combinations of gentamicin with tetracycline, ciprofloxacin, and ceftazidime against Multidrug-resistant MDR Klebsiella pneumoniae; tetracycline-ceftazidime combination against MDR Escherichia coli, colistin combinations with ceftazidime and gentamicin, and tetracycline-gentamicin combinations against MDR Citrobacter freundii may be future therapeutic alternatives. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
An investigation into the effect of dietary protein and fishmeal replacement in juvenile Yellowtail, seriola lalandi (pisces: carangidae) in a recirculating aquaculture system
- Manjingolo, Apelele https://orcid.org/0000-0003-3914-4821
- Authors: Manjingolo, Apelele https://orcid.org/0000-0003-3914-4821
- Date: 2023-01
- Subjects: Yellowtail , Integrated aquaculture , Yellowtail fisheries
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27489 , vital:67332
- Description: The yellowtail kingfish, Seriola lalandi, is a carnivorous species, which require high levels 40 Percent of protein in its diet of which a significant portion comes from fishmeal. Fishmeal is usually the main ingredient when formulating a diet for carnivorous fish because of its high protein content, good digestibility and balanced essential amino acid profile. The use of fishmeal in diet formulations has decreased because of high prices and short supply. Aquaculturists have little alternative but to reduce the amount used or replace it with alternative suitable protein sources. This study aimed to contribute to the optimization of protein requirements and fishmeal replacement in the diet of juvenile yellowtail in a Recirculating Aquaculture System RAS. This study was conducted at the marine finfish farm, Kingfish Enterprises Pty Ltd in the East London Industrial Development Zone ELIDZ in a purpose designed RAS. The first experiment investigated the effect of dietary protein level on survival, growth, food conversion ratio FCR and health of juvenile yellowtail in a RAS. Four iso-calorific diets containing different dietary protein levels 38 Percent , 44 Percent , 50 Percent and 56 Percent were formulated. Each diet was fed to three RAS tanks holding juvenile yellowtail 30 fish per tank for 49 days. Dietary protein levels did not influence survival of juvenile yellowtail. Specific growth rate SGR p equal 0.003) was greater in fish fed 56 Percent protein compared to fish fed 38 Percent protein but there were no differences between the 56 Percent , 50 Percent and 44 Percent protein diets. There were no differences in protein efficiency ratio PER between the four diets. FCR decreased with increasing protein level with fish being fed the 56 Percent protein yielding the lowest FCR 1.26 compared to fish fed 38 Percent protein 1.76 p equal 0.003, however, there was no difference between the 44 Percent , 50 Percent and 56 Percent protein levels. The hepatocytes of fish fed high dietary lipid content diet with 38 Percent and 44 Percent protein showed large lipid vacuole zones in the cytoplasm p greater 0.001. Body protein, ash, moisture, and lipid was not affected by different dietary protein levels. In terms of producing a diet with best growth at the lowest cost, a 44 Percent protein diet is considered as optimal for juvenile yellowtail in RAS. The second experiment investigated the effect of partial and full replacement of fishmeal with a mixture of alternative protein sources chicken meal, blood meal, and soybean meal in equal proportions that are more sustainable and less costly. Four experimental diets were formulated to be iso-nitrogenous 44 Percent protein and iso-calorific 19.50 Mg/Kg as follows: 1 a control diet with fishmeal as the only protein source which was the same formulation as the 44 Percent diet used in the first experiment, 2 control diet in which 33 Percent of fishmeal was replaced with the protein mixture, 3 control diet in which 67 Percent of fishmeal was replaced with the protein mixture and 4 control diet in which 100 Percent of fishmeal was replaced with the protein mixture. Different fishmeal levels in the diets did not have an effect on the survival on juvenile yellowtail. Specific growth rate SGR was greater for fish fed 67 and 100 Percent fishmeal p equal 0.017 compared to fish fed 0 Percent fishmeal. There were, however, no differences in SGR between fish fed 33, 67, and 100 Percent fishmeal. Condition factor CF was significantly affected by the interaction between dietary treatment and time with average values lower at the end of experiment compared to the start of the experiment. On day 28 p equal 0.02 and 49 p equal 0.01, CF of fish fed 67 and 100 Percent fishmeal diet differed significantly from those fed the 0 Percent fishmeal diet but 33, 67, and 100 Percent fishmeal diets did not differ from each other . Feed conversion ratio FCR was significantly affected by fishmeal replacement with fish on fishmeal-containing diets showing lower FCRs compared to those on fishmeal-free diets p equal 0.001. Fish fed diets containing 67 and 100 Percent fishmeal had low PER 0.026 compared to fish fed 0 Percent fishmeal. There were, however, no differences in PER between fish fed 33, 67, and 100 Percent fishmeal. Hepatosomatic index HSI was not affected by levels of fishmeal replacement in the diet. Body protein, ash, moisture, and lipid was not affected by partial and full replacement of fishmeal. The results indicate that full replacement of fishmeal 0 Percent diet had the worst SGR, FCR, and PER. The remaining three diets were statistically similar which suggests that a diet with 33 Percent fishmeal produces as good growth, FCR and PER as 67 and 100 Percent fishmeal diets. However, as there were also similarities in SGR and PER for the 0 and 33 Percent fishmeal diets, it is therefore recommended that future studies focus on the region between 33-67 Percent to find the optimal break point for the various growth indicators. This study has provided foundation for the formulation of yellowtail kingfish diet which is suitable for use in a RAS. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-01
- Authors: Manjingolo, Apelele https://orcid.org/0000-0003-3914-4821
- Date: 2023-01
- Subjects: Yellowtail , Integrated aquaculture , Yellowtail fisheries
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27489 , vital:67332
- Description: The yellowtail kingfish, Seriola lalandi, is a carnivorous species, which require high levels 40 Percent of protein in its diet of which a significant portion comes from fishmeal. Fishmeal is usually the main ingredient when formulating a diet for carnivorous fish because of its high protein content, good digestibility and balanced essential amino acid profile. The use of fishmeal in diet formulations has decreased because of high prices and short supply. Aquaculturists have little alternative but to reduce the amount used or replace it with alternative suitable protein sources. This study aimed to contribute to the optimization of protein requirements and fishmeal replacement in the diet of juvenile yellowtail in a Recirculating Aquaculture System RAS. This study was conducted at the marine finfish farm, Kingfish Enterprises Pty Ltd in the East London Industrial Development Zone ELIDZ in a purpose designed RAS. The first experiment investigated the effect of dietary protein level on survival, growth, food conversion ratio FCR and health of juvenile yellowtail in a RAS. Four iso-calorific diets containing different dietary protein levels 38 Percent , 44 Percent , 50 Percent and 56 Percent were formulated. Each diet was fed to three RAS tanks holding juvenile yellowtail 30 fish per tank for 49 days. Dietary protein levels did not influence survival of juvenile yellowtail. Specific growth rate SGR p equal 0.003) was greater in fish fed 56 Percent protein compared to fish fed 38 Percent protein but there were no differences between the 56 Percent , 50 Percent and 44 Percent protein diets. There were no differences in protein efficiency ratio PER between the four diets. FCR decreased with increasing protein level with fish being fed the 56 Percent protein yielding the lowest FCR 1.26 compared to fish fed 38 Percent protein 1.76 p equal 0.003, however, there was no difference between the 44 Percent , 50 Percent and 56 Percent protein levels. The hepatocytes of fish fed high dietary lipid content diet with 38 Percent and 44 Percent protein showed large lipid vacuole zones in the cytoplasm p greater 0.001. Body protein, ash, moisture, and lipid was not affected by different dietary protein levels. In terms of producing a diet with best growth at the lowest cost, a 44 Percent protein diet is considered as optimal for juvenile yellowtail in RAS. The second experiment investigated the effect of partial and full replacement of fishmeal with a mixture of alternative protein sources chicken meal, blood meal, and soybean meal in equal proportions that are more sustainable and less costly. Four experimental diets were formulated to be iso-nitrogenous 44 Percent protein and iso-calorific 19.50 Mg/Kg as follows: 1 a control diet with fishmeal as the only protein source which was the same formulation as the 44 Percent diet used in the first experiment, 2 control diet in which 33 Percent of fishmeal was replaced with the protein mixture, 3 control diet in which 67 Percent of fishmeal was replaced with the protein mixture and 4 control diet in which 100 Percent of fishmeal was replaced with the protein mixture. Different fishmeal levels in the diets did not have an effect on the survival on juvenile yellowtail. Specific growth rate SGR was greater for fish fed 67 and 100 Percent fishmeal p equal 0.017 compared to fish fed 0 Percent fishmeal. There were, however, no differences in SGR between fish fed 33, 67, and 100 Percent fishmeal. Condition factor CF was significantly affected by the interaction between dietary treatment and time with average values lower at the end of experiment compared to the start of the experiment. On day 28 p equal 0.02 and 49 p equal 0.01, CF of fish fed 67 and 100 Percent fishmeal diet differed significantly from those fed the 0 Percent fishmeal diet but 33, 67, and 100 Percent fishmeal diets did not differ from each other . Feed conversion ratio FCR was significantly affected by fishmeal replacement with fish on fishmeal-containing diets showing lower FCRs compared to those on fishmeal-free diets p equal 0.001. Fish fed diets containing 67 and 100 Percent fishmeal had low PER 0.026 compared to fish fed 0 Percent fishmeal. There were, however, no differences in PER between fish fed 33, 67, and 100 Percent fishmeal. Hepatosomatic index HSI was not affected by levels of fishmeal replacement in the diet. Body protein, ash, moisture, and lipid was not affected by partial and full replacement of fishmeal. The results indicate that full replacement of fishmeal 0 Percent diet had the worst SGR, FCR, and PER. The remaining three diets were statistically similar which suggests that a diet with 33 Percent fishmeal produces as good growth, FCR and PER as 67 and 100 Percent fishmeal diets. However, as there were also similarities in SGR and PER for the 0 and 33 Percent fishmeal diets, it is therefore recommended that future studies focus on the region between 33-67 Percent to find the optimal break point for the various growth indicators. This study has provided foundation for the formulation of yellowtail kingfish diet which is suitable for use in a RAS. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-01
The effect of the anaesthetics 1 Clove oil and MS-222 on the sedation, recovery, survival, population growth and fecundity of the calanoid copepod, Pseudodiaptomus hessei Copepoda Calanoida under culture conditions.
- Authors: Bulube, Masivuye Nomazizi
- Date: 2023-01
- Subjects: Water quality , Marine biodiversity , Aquatic animals -- Food
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27524 , vital:67430
- Description: Compared to current live food organisms used in aquaculture, the calanoid copepod, Pseudodiaptomus hessei is smaller and has a superior nutritional value. However, due to their fast and erratic movements, manipulating and counting this species for aquaculture research purposes is difficult. For easier manipulation it is therefore necessary to sedate the copepods. The study aimed to determine the effect of two anaesthetics on sedation, recovery, survival, population growth and fecundity of the calanoid copepod, Pseudodiaptomus hessei, under culture conditions. Male and female P. hessei were exposed to the anaesthetics clove oil and Tricaine Methane sulfonate (MS-222). Twelve replicates of five copepods each were exposedto clove oil at 100, 150 and 200 μL/L, and to MS-222 at 300, 600, 900, 1200 and 1500 mg/Lwith the number of fully sedated copepods being recorded. clove oil sedation only occurredafter 5:23±1:25 minutes in the 100 μL/L treatment while copepods exposed to 150 and200μL/L were anaesthetized within 2:48±0:46 and 0:40±0:07 minutes respectively. Sedation did not occur in MS-222 at concentrations of 300 and 600 mg/L while at 900 mg/L all copepodswere sedated within 4:19±0:41 minutes. Only copepods exposed to 1200 and 1500 mg/L were all fully sedated within 2:26±1:46 and 1:23±0:37 minutes respectively. Clove oil recovery onlyoccurred at 4:40±1:32 minutes in the 100 μL/L treatment while copepods exposed to 150 and200 μL/L recovered at 8:30±1:46 and 12:12±0:59 minutes, respectively. In this study, all MS- 222 treatments showed full recovery at 1:07±0:41 to 1:11±0:41 minutes with 100% survivalrate. The growth development FPN (Final Population Number) for Clove oil, MS-222 and control were not different from the control indicating that exposure to the anaesthetic had no effect on their long-term survival (21 days). The mean clutch size of 34±5 eggs per sac was high compared to other studies on the species. Based on these findings the 150 μL/L Clove oiland 1200 mg/L MS-222 concentrations were the lowest doses of each anaesthetic to induce full sedation within 3 minutes followed by rapid recovery 87 within three minutes without it affecting its short (24 hours) and long-term survival, population growth and fecundity. Basedon sedation and recovery rates, effect on survival, fecundity and growth as well as cost and ease use, the 1200 mg/L MS-222 concentration is the recommended to safely anaesthetize P. hessei. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-01
- Authors: Bulube, Masivuye Nomazizi
- Date: 2023-01
- Subjects: Water quality , Marine biodiversity , Aquatic animals -- Food
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27524 , vital:67430
- Description: Compared to current live food organisms used in aquaculture, the calanoid copepod, Pseudodiaptomus hessei is smaller and has a superior nutritional value. However, due to their fast and erratic movements, manipulating and counting this species for aquaculture research purposes is difficult. For easier manipulation it is therefore necessary to sedate the copepods. The study aimed to determine the effect of two anaesthetics on sedation, recovery, survival, population growth and fecundity of the calanoid copepod, Pseudodiaptomus hessei, under culture conditions. Male and female P. hessei were exposed to the anaesthetics clove oil and Tricaine Methane sulfonate (MS-222). Twelve replicates of five copepods each were exposedto clove oil at 100, 150 and 200 μL/L, and to MS-222 at 300, 600, 900, 1200 and 1500 mg/Lwith the number of fully sedated copepods being recorded. clove oil sedation only occurredafter 5:23±1:25 minutes in the 100 μL/L treatment while copepods exposed to 150 and200μL/L were anaesthetized within 2:48±0:46 and 0:40±0:07 minutes respectively. Sedation did not occur in MS-222 at concentrations of 300 and 600 mg/L while at 900 mg/L all copepodswere sedated within 4:19±0:41 minutes. Only copepods exposed to 1200 and 1500 mg/L were all fully sedated within 2:26±1:46 and 1:23±0:37 minutes respectively. Clove oil recovery onlyoccurred at 4:40±1:32 minutes in the 100 μL/L treatment while copepods exposed to 150 and200 μL/L recovered at 8:30±1:46 and 12:12±0:59 minutes, respectively. In this study, all MS- 222 treatments showed full recovery at 1:07±0:41 to 1:11±0:41 minutes with 100% survivalrate. The growth development FPN (Final Population Number) for Clove oil, MS-222 and control were not different from the control indicating that exposure to the anaesthetic had no effect on their long-term survival (21 days). The mean clutch size of 34±5 eggs per sac was high compared to other studies on the species. Based on these findings the 150 μL/L Clove oiland 1200 mg/L MS-222 concentrations were the lowest doses of each anaesthetic to induce full sedation within 3 minutes followed by rapid recovery 87 within three minutes without it affecting its short (24 hours) and long-term survival, population growth and fecundity. Basedon sedation and recovery rates, effect on survival, fecundity and growth as well as cost and ease use, the 1200 mg/L MS-222 concentration is the recommended to safely anaesthetize P. hessei. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-01
Grain size analysis, coastal hydrodynamics and erosion protection: a case study from Knysna and Plettenberg Bay, South Africa
- Authors: Pezisa, Ayabulela Raymond
- Date: 2022-12
- Subjects: Grain -- Analysis , Hydrodynamics , Shore protection
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27698 , vital:69394
- Description: The modern beach sands and Cretaceous Knysna Formation distributed along the coast of Plettenberg Bay and Knysna coast in the Western Cape Province of South Africa, have been examined and studied in the field outcrops and laborataries via grain-size analysis, XRD, SEM, EDX and microcope petrography analyses. This study looked into the coastal hydrodynamics and environment protection. The project aims to investigate the sediment distribution, grain-size variation, sedimentary structures, coast erosion and mitigation in the Plettenberg and Knysna coast to address environmental issues in the south coast of South Africa. The research will provide new insight onto coastal sedimentation, hydrodynamic condition, coastline erosion and the safety of the coastal environment and human property. The study will promote government attention on the sea level change, which caused flooding and environmental disaster along the south coastal area of South Africa. The rock sequence in the inland side of the study areas belongs to Cretaceous Knysna Formation, which comprises seven upward fining sequences. The stratigraphic sequence is underlain by the Table Mountain quartzite of the Cape Supergroup, and is overlain by Tertiary sediments and modern coastal dune sands. The Knysna Formation at the research area consists of massive conglomerate, sandstone and minor mudstone of mainly fluvial dominated sediments. The grain size analysis reveals that the modern fluvial channels at Plettenberg Bay and Knysna areas are of dominant coarse sands with minor silt and mud, which defines the sediments were deposited by moderate to high energy currents. Whilst the beach zones in Plettenberg Bay are predominated by fine to medium-grained marine sands. Grain-size analyses of beach sands show well-sorted, fine to coarse skewed in grain size distribution, indicating a relative lower to medium uniform energy condition during transportation and deposition. The bivariate plots of grain-size distribution demonstrate of the shallow agitated marine environment with the influence of tide and aeolian processes. Hydrodynamic condition in the beach area was more persistant and less variation compared to the river environment. The mineralogy and petrology studies revealed that in Plettenberg Bay and Knysna sediments are predominantly consisted of minerals quartz, feldspar, calcite, muscovite, aragonite, clay minerals, and salts (halite). Skeletal carbonate minerals (shell and coral fragments) are more than chemical precipitated carbonate minerals. The microtextures detected on the surface of the fluvial and marine sand grais involve V-shaped pits, upturn pits, dissolution pits and secondary mineral precipitation that were created by chemical and mechanical processes formed via sea-water dissolution, corrosion, and transport crashing. Whereas the boring holes and burrows created by activity of microorganisms boing into the surface of the grains. These microtextures of the river and beach sands exhibit a shallow marine and fluvial environments with medium to high energy conditions and active organic activities. Several sedimentary structures were detected in the coastal environments, including various types of ripple marks and dunes, burst bubble-hole, swash line, rill marks, rhomboid marks, burrows, boring and bioturbation, planar lamination and gravel pavement. In addition, sedimentary structures were also identified in the Cretaceous Knysna Formation such as air/water escape hole, convolute bedding, lenticular bedding, tabular cross-bedding and load cast. The sedimetnary structures closely linked with hydrodynamic conditions and therefore can be used as indicators for depositional environments. Flooding and erosion had become a coastal disaster that results in sediment redistribution throughout the coastal system and therefore caused landscape reform like coastal cliffs and sharpened dunes in erosive areas. Particularly, coastal hazards become more and more serious in recent years due to climate and sea leavel changes. Thus, to recognise coastal erosion and disaster and make a management strategy is of significant importance to compete against coastline retreat and to protect infrastructure and human safety in the coast area. The author had proposed a number of mitigation methods for environmental protection and for combating coastal erosion, including breakwaters, groins, jetties, vertical walls, rock armour, vegetation, boundary hardening, and revetment etc, which are the effective ways for protection of coast retreat, property damage and human safety. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Pezisa, Ayabulela Raymond
- Date: 2022-12
- Subjects: Grain -- Analysis , Hydrodynamics , Shore protection
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27698 , vital:69394
- Description: The modern beach sands and Cretaceous Knysna Formation distributed along the coast of Plettenberg Bay and Knysna coast in the Western Cape Province of South Africa, have been examined and studied in the field outcrops and laborataries via grain-size analysis, XRD, SEM, EDX and microcope petrography analyses. This study looked into the coastal hydrodynamics and environment protection. The project aims to investigate the sediment distribution, grain-size variation, sedimentary structures, coast erosion and mitigation in the Plettenberg and Knysna coast to address environmental issues in the south coast of South Africa. The research will provide new insight onto coastal sedimentation, hydrodynamic condition, coastline erosion and the safety of the coastal environment and human property. The study will promote government attention on the sea level change, which caused flooding and environmental disaster along the south coastal area of South Africa. The rock sequence in the inland side of the study areas belongs to Cretaceous Knysna Formation, which comprises seven upward fining sequences. The stratigraphic sequence is underlain by the Table Mountain quartzite of the Cape Supergroup, and is overlain by Tertiary sediments and modern coastal dune sands. The Knysna Formation at the research area consists of massive conglomerate, sandstone and minor mudstone of mainly fluvial dominated sediments. The grain size analysis reveals that the modern fluvial channels at Plettenberg Bay and Knysna areas are of dominant coarse sands with minor silt and mud, which defines the sediments were deposited by moderate to high energy currents. Whilst the beach zones in Plettenberg Bay are predominated by fine to medium-grained marine sands. Grain-size analyses of beach sands show well-sorted, fine to coarse skewed in grain size distribution, indicating a relative lower to medium uniform energy condition during transportation and deposition. The bivariate plots of grain-size distribution demonstrate of the shallow agitated marine environment with the influence of tide and aeolian processes. Hydrodynamic condition in the beach area was more persistant and less variation compared to the river environment. The mineralogy and petrology studies revealed that in Plettenberg Bay and Knysna sediments are predominantly consisted of minerals quartz, feldspar, calcite, muscovite, aragonite, clay minerals, and salts (halite). Skeletal carbonate minerals (shell and coral fragments) are more than chemical precipitated carbonate minerals. The microtextures detected on the surface of the fluvial and marine sand grais involve V-shaped pits, upturn pits, dissolution pits and secondary mineral precipitation that were created by chemical and mechanical processes formed via sea-water dissolution, corrosion, and transport crashing. Whereas the boring holes and burrows created by activity of microorganisms boing into the surface of the grains. These microtextures of the river and beach sands exhibit a shallow marine and fluvial environments with medium to high energy conditions and active organic activities. Several sedimentary structures were detected in the coastal environments, including various types of ripple marks and dunes, burst bubble-hole, swash line, rill marks, rhomboid marks, burrows, boring and bioturbation, planar lamination and gravel pavement. In addition, sedimentary structures were also identified in the Cretaceous Knysna Formation such as air/water escape hole, convolute bedding, lenticular bedding, tabular cross-bedding and load cast. The sedimetnary structures closely linked with hydrodynamic conditions and therefore can be used as indicators for depositional environments. Flooding and erosion had become a coastal disaster that results in sediment redistribution throughout the coastal system and therefore caused landscape reform like coastal cliffs and sharpened dunes in erosive areas. Particularly, coastal hazards become more and more serious in recent years due to climate and sea leavel changes. Thus, to recognise coastal erosion and disaster and make a management strategy is of significant importance to compete against coastline retreat and to protect infrastructure and human safety in the coast area. The author had proposed a number of mitigation methods for environmental protection and for combating coastal erosion, including breakwaters, groins, jetties, vertical walls, rock armour, vegetation, boundary hardening, and revetment etc, which are the effective ways for protection of coast retreat, property damage and human safety. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-12
Estimating estuarine suspended sediment concentration through spectral indices and band ratios derived from Sentinel-2 data: a case of Umzimvubu Estuary, South Africa
- Authors: Tshazi, Zamavuso
- Date: 2022-11
- Subjects: Sediments (Geology) , Suspended sediments , Remote sensing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27743 , vital:69406
- Description: The current study was aimed at evaluating the reliability and efficacy of selected remote sensing band ratios and indices in accurately estimating the spatial patterns of suspended sediment concentration level in Umzimvubu Estuary, Eastern Cape, South Africa. Sentinel-2 imagery was acquired on the 29th of March 2022. Band reflectance values were extracted from Sentinel -2 imagery, and laboratory measurements of suspended sediment concentration were obtained from samples collected from fifty (50) sampling points in the estuary on the 29th of March 2022. Sentinel-2 imagery was then validated with the field data in estimating and mapping the suspended sediment concentration. Several remote sensing band ratios Red/(Green plus Near-Infrared), Near-Infrared/Green, Red plus Near-Infrared/Green, Blue(Green plus Red)/Blue and Green plus Near-Infrared)/Blue and indices, that is the Normalised Difference Turbidity Index (NDTI), Normalized Difference Suspended Sediment Index (NDSSI) and Normalized Suspended Material Index (NSMI)) were then used to predict the suspended sediment concentration from Sentinel-2 imagery. The accuracy of band ratios and indices was evaluated by correlating the prediction against the observed suspended sediment concentration from Sentinel-2 imagery. A total of 50 points were randomly surveyed in the Umzimvubu estuary for analyzing suspended sediment concentration. Results indicate that the Blue (Green plus Red)/Blue, the Green plus Near-Infrared)/Blue and NMSI performed well based on their R-squared. The Blue (Green plus Red)/Blue and Green + Near-Infrared)/Blue band ratios had 0.86 and 0, 94, respectively. While NSMI yielded an R-squared of 0,76 and RMSE of 19,2 mg/L. The results in the current study indicate that Sentinel-2 imagery can reliably estimate the concentration of suspended sediment level in the Umzimvubu Estuary using band ratios and indices. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Tshazi, Zamavuso
- Date: 2022-11
- Subjects: Sediments (Geology) , Suspended sediments , Remote sensing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27743 , vital:69406
- Description: The current study was aimed at evaluating the reliability and efficacy of selected remote sensing band ratios and indices in accurately estimating the spatial patterns of suspended sediment concentration level in Umzimvubu Estuary, Eastern Cape, South Africa. Sentinel-2 imagery was acquired on the 29th of March 2022. Band reflectance values were extracted from Sentinel -2 imagery, and laboratory measurements of suspended sediment concentration were obtained from samples collected from fifty (50) sampling points in the estuary on the 29th of March 2022. Sentinel-2 imagery was then validated with the field data in estimating and mapping the suspended sediment concentration. Several remote sensing band ratios Red/(Green plus Near-Infrared), Near-Infrared/Green, Red plus Near-Infrared/Green, Blue(Green plus Red)/Blue and Green plus Near-Infrared)/Blue and indices, that is the Normalised Difference Turbidity Index (NDTI), Normalized Difference Suspended Sediment Index (NDSSI) and Normalized Suspended Material Index (NSMI)) were then used to predict the suspended sediment concentration from Sentinel-2 imagery. The accuracy of band ratios and indices was evaluated by correlating the prediction against the observed suspended sediment concentration from Sentinel-2 imagery. A total of 50 points were randomly surveyed in the Umzimvubu estuary for analyzing suspended sediment concentration. Results indicate that the Blue (Green plus Red)/Blue, the Green plus Near-Infrared)/Blue and NMSI performed well based on their R-squared. The Blue (Green plus Red)/Blue and Green + Near-Infrared)/Blue band ratios had 0.86 and 0, 94, respectively. While NSMI yielded an R-squared of 0,76 and RMSE of 19,2 mg/L. The results in the current study indicate that Sentinel-2 imagery can reliably estimate the concentration of suspended sediment level in the Umzimvubu Estuary using band ratios and indices. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Examining the nature of entrepreneurship within the towns and rural areas of Sakhisizwe Local Municipality, Eastern Cape
- Authors: Maliwa, Noluvuyo
- Date: 2022-11
- Subjects: Entrepreneurship , Developing countries--Economic conditions , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27555 , vital:69315
- Description: Entrepreneurship plays an important role in societies around the world because it supports economic growth and creates job opportunities. This study investigated the nature of entrepreneurship in three distinct parts of Sakhisizwe Local Municipality, including a town within Sakhisizwe’s former homeland area, rural communities within its former homeland area, and a town within an area characterised by large-scale commercial farms. The study sought to establish the share of adults in the different parts of the municipality involved in entrepreneurship, to identify factors that contribute to the decision to become an entrepreneur, and to examine strategies pursued by, and challenges experienced, different types of entrepreneurs. The study involved a random sample of 362 respondents and both quantitative and qualitative data analysis. Among the main findings is that the proportion of adults involved in enterprise in Sakhisizwe is higher than found by other studies for South Africa as a whole, but is especially high for those living in the town in the former homeland area. While those residing in rural communities also engage in enterprise, they are generally compelled to practice their enterprises in town, thus have the disadvantage of needing frequent transport. While residing in the town in the commercial farming area is not disadvantageous in the same way, the challenge is that the town itself is able to support relatively few entrepreneurs due to fewer people coming to town for their shopping. , Thesis (MSci) -- Faculty of Science and Agricultures, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Maliwa, Noluvuyo
- Date: 2022-11
- Subjects: Entrepreneurship , Developing countries--Economic conditions , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27555 , vital:69315
- Description: Entrepreneurship plays an important role in societies around the world because it supports economic growth and creates job opportunities. This study investigated the nature of entrepreneurship in three distinct parts of Sakhisizwe Local Municipality, including a town within Sakhisizwe’s former homeland area, rural communities within its former homeland area, and a town within an area characterised by large-scale commercial farms. The study sought to establish the share of adults in the different parts of the municipality involved in entrepreneurship, to identify factors that contribute to the decision to become an entrepreneur, and to examine strategies pursued by, and challenges experienced, different types of entrepreneurs. The study involved a random sample of 362 respondents and both quantitative and qualitative data analysis. Among the main findings is that the proportion of adults involved in enterprise in Sakhisizwe is higher than found by other studies for South Africa as a whole, but is especially high for those living in the town in the former homeland area. While those residing in rural communities also engage in enterprise, they are generally compelled to practice their enterprises in town, thus have the disadvantage of needing frequent transport. While residing in the town in the commercial farming area is not disadvantageous in the same way, the challenge is that the town itself is able to support relatively few entrepreneurs due to fewer people coming to town for their shopping. , Thesis (MSci) -- Faculty of Science and Agricultures, 2022
- Full Text:
- Date Issued: 2022-11
Insights into the drivers and impact of climate change and climate change adaptation in the Eastern Cape, South Africa: the case of Amathole District Municipality
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Spatial assessment of riparian vegetation condition in relation to water quality: a case of the Keiskamma River, Eastern Cape Province, South Africa
- Authors: Teyise, Anda
- Date: 2022-11
- Subjects: Water quality , Riparian plants , Stream health
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27679 , vital:69393
- Description: Riparian vegetation plays several roles in ecological functioning, such as improving water quality because it can filtrate the sediments and provides stability on the floodplain. The condition of riparian vegetation can serve to provide information regarding river condition. The main purpose of this study was to investigate the extent to which water quality level of the Keiskamma River can be explained by the riparian vegetation density patterns. This study used Sentinel-2 Multi-Spectral Instrument (MSI) satellite image to assess spatial patterns in riparian vegetation condition. The Normalized Difference Vegetation Index (NDVI) was generated from the Sentinel-2 imagery and was used as the base from which riparian vegetation density classes were obtained through the supervised image classification technique. The image classification accuracy assessment was caried out to verify and validate the accuracy of riparian vegetation density classes. This technique produced the overall accuracy (OA) classification of 83.72 percent. The riverine water quality parameters were measured on the randomly surveyed sites using the Premium Series PC60 5-in-1 Water Quality Tester. High density of riparian vegetation were found in the upper course of the river. The low-density riparian vegetation dominates the middle course of the river while the lower part of the river contains a mixture of the three riparian vegetation conditions. The one-sample t-test statistical technique was carried out to determine the spatial pattern of water quality parameters. The t-test results revealed the significant variation in water pH, with the p-value of 0.00. However, t-test results also showed insignificant variations in water Total Dissolved Solids (TDS) and electrical conductivity (EC), with p-values of 0.117 0.059 and 0.059 respectively. The linear regression was used to determine the relationship between riparian vegetation and water quality. In this case, the NDVI values were used as surrogate for riparian vegetation condition. The results showed insignificant relationships between NDVI and water pH (r2 = 0.00), NDVI and water TDS (r2 = 0.09), and NDVI and water EC (r2 = 0.09) along the Keiskamma River. In view of the findings obtained from this study “spatial differences in riparian vegetation along the lateral and longitudinal dimensions of the Keiskamma River denote spatial variations in water quality levels”, is rejected. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Teyise, Anda
- Date: 2022-11
- Subjects: Water quality , Riparian plants , Stream health
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27679 , vital:69393
- Description: Riparian vegetation plays several roles in ecological functioning, such as improving water quality because it can filtrate the sediments and provides stability on the floodplain. The condition of riparian vegetation can serve to provide information regarding river condition. The main purpose of this study was to investigate the extent to which water quality level of the Keiskamma River can be explained by the riparian vegetation density patterns. This study used Sentinel-2 Multi-Spectral Instrument (MSI) satellite image to assess spatial patterns in riparian vegetation condition. The Normalized Difference Vegetation Index (NDVI) was generated from the Sentinel-2 imagery and was used as the base from which riparian vegetation density classes were obtained through the supervised image classification technique. The image classification accuracy assessment was caried out to verify and validate the accuracy of riparian vegetation density classes. This technique produced the overall accuracy (OA) classification of 83.72 percent. The riverine water quality parameters were measured on the randomly surveyed sites using the Premium Series PC60 5-in-1 Water Quality Tester. High density of riparian vegetation were found in the upper course of the river. The low-density riparian vegetation dominates the middle course of the river while the lower part of the river contains a mixture of the three riparian vegetation conditions. The one-sample t-test statistical technique was carried out to determine the spatial pattern of water quality parameters. The t-test results revealed the significant variation in water pH, with the p-value of 0.00. However, t-test results also showed insignificant variations in water Total Dissolved Solids (TDS) and electrical conductivity (EC), with p-values of 0.117 0.059 and 0.059 respectively. The linear regression was used to determine the relationship between riparian vegetation and water quality. In this case, the NDVI values were used as surrogate for riparian vegetation condition. The results showed insignificant relationships between NDVI and water pH (r2 = 0.00), NDVI and water TDS (r2 = 0.09), and NDVI and water EC (r2 = 0.09) along the Keiskamma River. In view of the findings obtained from this study “spatial differences in riparian vegetation along the lateral and longitudinal dimensions of the Keiskamma River denote spatial variations in water quality levels”, is rejected. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
The classification performance of ensemble decision tree classifiers: a case study of detecting fraud in credit card transactions
- Authors: Chogugudza, Mcdonald
- Date: 2022-11
- Subjects: fraud , Commercial fraud , Accounting fraud
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27590 , vital:69317
- Description: In this dissertation, we propose ensemble decision tree classifiers as an ideal classification technique for solving the problem of fraud in the domain of credit card transactions. Ensemble tree classifiers have been applied in many areas like speech recognition, image recognition and medical diagnostics and have shown excellent results. At the centre of fraud, credit card fraud has been a major concern. The rise in credit card fraud is largely attributed to the nature in which it can be done. A fraudster does not need to always be physically present to commit fraud making it the number one target for criminals. Card-Not-Present refers to this type of fraud where an electronic transaction can be conducted without the need for a client to be present. This can be done via telephonic calls or the web. To be able to come up with better classifiers it was important for the researcher to first investigate what causes misclassifications in fraud detection systems. A systematic literature review was done to uncover the factors that have been identified as causes of misclassifications. It was discovered that many factors lead to misclassifications and several authors have proposed techniques to handle these factors. However, there is no universal techniques for addressing factors that lead to misclassifications as different domains have different datasets which require different techniques. This study investigates how parameters involved in modelling fraud detection systems impact the classification performance of ensemble decision tree classifiers. The factors that were investigated include sample size, sampling technique, learning method and choice of split criterion and how they affect classification performance. A series of experiments were conducted to investigate how the aforementioned factors contributed to better classifiers. Ecommerce data from Vesta corporation made available on Kaggle was used in the experiments. The data was split into two sets, one for training the models and the other for testing the performance of the models. Accuracy, confusion matrix, precision and recall were used as performance measures. Our results showed that a larger sample size resulted in better classifiers. This is attributed to models having more instances to learn from which covers most patterns of fraudulent transactions. The sampling technique was shown to be pivotal in classification performance as under sampling showed a great reduction in performance as it achieved a maximum accuracy of 89.6223 while oversampling produced increased performance with maximum accuracy of 99.9531. Furthermore, our results showed that the choice of split criterion impacts the performance of ensemble tree classifiers. The use of entropy as the choice of split criterion resulted in better classifiers compared to the use of the Gini index. However, the downside is that entropy requires more time to execute compared to the Gini index. Lastly, the learning method proved to impact the performance of ensemble classifiers. Models that used supervised learning had better performance compared to those that use unsupervised learning in detecting credit card fraud. The conclusions from this research are insightful when designing fraud detection systems that use ensemble decision tree classifiers as base learners. , Thesis (Msci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Chogugudza, Mcdonald
- Date: 2022-11
- Subjects: fraud , Commercial fraud , Accounting fraud
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27590 , vital:69317
- Description: In this dissertation, we propose ensemble decision tree classifiers as an ideal classification technique for solving the problem of fraud in the domain of credit card transactions. Ensemble tree classifiers have been applied in many areas like speech recognition, image recognition and medical diagnostics and have shown excellent results. At the centre of fraud, credit card fraud has been a major concern. The rise in credit card fraud is largely attributed to the nature in which it can be done. A fraudster does not need to always be physically present to commit fraud making it the number one target for criminals. Card-Not-Present refers to this type of fraud where an electronic transaction can be conducted without the need for a client to be present. This can be done via telephonic calls or the web. To be able to come up with better classifiers it was important for the researcher to first investigate what causes misclassifications in fraud detection systems. A systematic literature review was done to uncover the factors that have been identified as causes of misclassifications. It was discovered that many factors lead to misclassifications and several authors have proposed techniques to handle these factors. However, there is no universal techniques for addressing factors that lead to misclassifications as different domains have different datasets which require different techniques. This study investigates how parameters involved in modelling fraud detection systems impact the classification performance of ensemble decision tree classifiers. The factors that were investigated include sample size, sampling technique, learning method and choice of split criterion and how they affect classification performance. A series of experiments were conducted to investigate how the aforementioned factors contributed to better classifiers. Ecommerce data from Vesta corporation made available on Kaggle was used in the experiments. The data was split into two sets, one for training the models and the other for testing the performance of the models. Accuracy, confusion matrix, precision and recall were used as performance measures. Our results showed that a larger sample size resulted in better classifiers. This is attributed to models having more instances to learn from which covers most patterns of fraudulent transactions. The sampling technique was shown to be pivotal in classification performance as under sampling showed a great reduction in performance as it achieved a maximum accuracy of 89.6223 while oversampling produced increased performance with maximum accuracy of 99.9531. Furthermore, our results showed that the choice of split criterion impacts the performance of ensemble tree classifiers. The use of entropy as the choice of split criterion resulted in better classifiers compared to the use of the Gini index. However, the downside is that entropy requires more time to execute compared to the Gini index. Lastly, the learning method proved to impact the performance of ensemble classifiers. Models that used supervised learning had better performance compared to those that use unsupervised learning in detecting credit card fraud. The conclusions from this research are insightful when designing fraud detection systems that use ensemble decision tree classifiers as base learners. , Thesis (Msci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Isolation, characterisation and biological evaluation of Tithonia diversifolia and Tephrosia vogelii as sources of Anti-oxidant and Pesticide
- Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Authors: Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Date: 2022-08
- Subjects: Tephrosia vogelii , Tephrosia , Pesticides
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27821 , vital:69943
- Description: This study aimed at evaluating chemically the pesticidal and antioxidant activities of Tithonia diversifolia Hemsland Tephrosia vogelii Hook f. In the study, the composition of essential oils and non-volatile substances was evaluated by modern analytical tools. The essential oils were characterised using Gas chromatography GC mass spectrometry mass spectrometry GC MS MS, GC and multivariate techniques. While phenolic compounds of T. diversifolia were comprehensively characterised using Ultra high performance liquid-phase chromatography coupled to a tandem mass spectrometer with electrospray ionisation UHPLC ESI MS MS. Both the essential oils and non-volatile components of the plant materials were evaluated for repellency, fumigant toxicity, contact toxicity and antifeedant potential in either a choice or no choice experiments. The non-volatile substances were evaluated for antioxidant properties. Using activity-guided isolation, three known compounds, a one pimarane diterpene type compound; sandaracopimaradiene-1α,9α-diol, a sesquiterpene lactone; deacetylviguiestenin and a caffeic acid derivative; 3 4 O caffeoyloxy methyl 2-methyloxirane-2-carboxylic acid were obtained from T. diversifolia. The compounds were characterised by spectral methods; 1D and 2D nuclear magnetic resonance NMR, Fourier transform Infra-red spectroscopy FTIR and mass spectrometry MS. Characterisation of essential oils revealed three chemotypes that were found to grow at different places of eastern Uganda. Based on the profiles of the compounds of the farnesene family, results showed that farnesol was a major constituent in the oil of chemotype 1 while springene compounds β-springene and α-springene and the β-farnesene were widely expressed in chemotype 2. The third chemotype was a mixed hybrid of both farnesol and the springene chemotypes. In all the chemotypes, alkylbenzenes; o-xylene, m-xylene and ethylbenzene were in huge amounts as other significant components in the oil. 1,4- dihydroxy-p-menth-2-ene, 5,9-undecadien-2-one, 6,10-dimethyl, and 3-cyclohexen-1- carboxaldehyde,3,4-dimethyl were other most significant chemical constituents of the three chemotypes. The presence of chemical variation in the components of T. vogelii essential oil showed that the fumigant and repellency efficacy of this plant against Sitophilus zeamais Motschulsky were undermined. However, all the chemotypes of T. vogelii essential oil could show repellence and fumigant toxicity against S. zeamais. The comparison between insecticidal and repellent effects of the essential oils of chemotype 3 of T. vogelii with that of T. diversifolia was done. Results indicated that the former could be promoted more for contact toxicity effect while T. diversifolia better suits fumigation effects against S. zeamais. Investigation of the feeding deterrence of both volatile and non-volatile substances of T. diversifolia leaves revealed that its essential oil did not show significant antifeedant activity at a dose of 0.29 μL mg of flour disks. The crude extract, some fractions and the isolated compounds demonstrated feeding deterrence activity against S. zeamais. The feeding deterrence index of sandarac copimaradiene- 1α,9α-diol was 81.19 5.94 percent at 0.1percent w w 1 mg g food compared to 97.45 0.43 percentage for Neemazal extract 10 percent azadirachtin positive control at 10w w 100 mgg food. The EC50 of deacetylviguiestin, 3 4 O caffeoyloxy methyl 2 methyloxirane 2 carboxylic acid and azadirachtin commercial antifeedant against S. zeamais were 22140.23 9103.29, 3654.28 2715.09 and 14.59 5.59 ppm respectively. Although these compounds showed less activity against S. zeamais than azadirachtin, their antifeedant activities were very significant and can be valuable alternatives. UHPLC DAD ESI-MS MS characterisation of fractions of T. diversifolia led to the identification of 7 novel hydroxycinnamates; 4-O 1 O caffeoylglucosyl quinic acid, 4 O caffeoyl 2 hydroxy 3 methylbutanoic acid, 4-O-caffeoyl-2-hydroxybutanoic acid, 3,4 dihydroxyphenyl-4-O-caffeoyl-2-hydroxybutanoate, 4-vinylphenyl 4 O caffeoyl 2-hydroxy 3 methylbutanoate, 4 O caffeoyl-caffeoyloxymethyl 2 hydroxy 3 methylbutanoate, 4 O-caffeoyl 2 2 3,4 dihydroxyphenyl acetoyloxy 3-methylbutanoic acid from T. diversifolia leaves that had not been previously reported in nature. Their structures have been assigned based on the unique MS MS fragmentation patterns for each of the compounds in a switching negative or positive ionisation mode and deduction from 1D 1H and 13C NMR of similar compound. In total, 55 phenolic compounds from aqueous fractions of T. diversifolia have been identified including 4 hydroxybenzoic acids, 19 hydroxycinnamic acids, 22 flavonoids, 1 saponin triterpenoid and 9 coumarins and furocoumarins. The present study further showed that the DPPH radical scavenging effect and reducing power antioxidant activity of tested samples of T. diversifolia showed a moderate correlation with the phenolic content present in these samples. This implied that the antioxidant potential was just partly attributed to its phenolic content. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-08
- Authors: Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Date: 2022-08
- Subjects: Tephrosia vogelii , Tephrosia , Pesticides
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27821 , vital:69943
- Description: This study aimed at evaluating chemically the pesticidal and antioxidant activities of Tithonia diversifolia Hemsland Tephrosia vogelii Hook f. In the study, the composition of essential oils and non-volatile substances was evaluated by modern analytical tools. The essential oils were characterised using Gas chromatography GC mass spectrometry mass spectrometry GC MS MS, GC and multivariate techniques. While phenolic compounds of T. diversifolia were comprehensively characterised using Ultra high performance liquid-phase chromatography coupled to a tandem mass spectrometer with electrospray ionisation UHPLC ESI MS MS. Both the essential oils and non-volatile components of the plant materials were evaluated for repellency, fumigant toxicity, contact toxicity and antifeedant potential in either a choice or no choice experiments. The non-volatile substances were evaluated for antioxidant properties. Using activity-guided isolation, three known compounds, a one pimarane diterpene type compound; sandaracopimaradiene-1α,9α-diol, a sesquiterpene lactone; deacetylviguiestenin and a caffeic acid derivative; 3 4 O caffeoyloxy methyl 2-methyloxirane-2-carboxylic acid were obtained from T. diversifolia. The compounds were characterised by spectral methods; 1D and 2D nuclear magnetic resonance NMR, Fourier transform Infra-red spectroscopy FTIR and mass spectrometry MS. Characterisation of essential oils revealed three chemotypes that were found to grow at different places of eastern Uganda. Based on the profiles of the compounds of the farnesene family, results showed that farnesol was a major constituent in the oil of chemotype 1 while springene compounds β-springene and α-springene and the β-farnesene were widely expressed in chemotype 2. The third chemotype was a mixed hybrid of both farnesol and the springene chemotypes. In all the chemotypes, alkylbenzenes; o-xylene, m-xylene and ethylbenzene were in huge amounts as other significant components in the oil. 1,4- dihydroxy-p-menth-2-ene, 5,9-undecadien-2-one, 6,10-dimethyl, and 3-cyclohexen-1- carboxaldehyde,3,4-dimethyl were other most significant chemical constituents of the three chemotypes. The presence of chemical variation in the components of T. vogelii essential oil showed that the fumigant and repellency efficacy of this plant against Sitophilus zeamais Motschulsky were undermined. However, all the chemotypes of T. vogelii essential oil could show repellence and fumigant toxicity against S. zeamais. The comparison between insecticidal and repellent effects of the essential oils of chemotype 3 of T. vogelii with that of T. diversifolia was done. Results indicated that the former could be promoted more for contact toxicity effect while T. diversifolia better suits fumigation effects against S. zeamais. Investigation of the feeding deterrence of both volatile and non-volatile substances of T. diversifolia leaves revealed that its essential oil did not show significant antifeedant activity at a dose of 0.29 μL mg of flour disks. The crude extract, some fractions and the isolated compounds demonstrated feeding deterrence activity against S. zeamais. The feeding deterrence index of sandarac copimaradiene- 1α,9α-diol was 81.19 5.94 percent at 0.1percent w w 1 mg g food compared to 97.45 0.43 percentage for Neemazal extract 10 percent azadirachtin positive control at 10w w 100 mgg food. The EC50 of deacetylviguiestin, 3 4 O caffeoyloxy methyl 2 methyloxirane 2 carboxylic acid and azadirachtin commercial antifeedant against S. zeamais were 22140.23 9103.29, 3654.28 2715.09 and 14.59 5.59 ppm respectively. Although these compounds showed less activity against S. zeamais than azadirachtin, their antifeedant activities were very significant and can be valuable alternatives. UHPLC DAD ESI-MS MS characterisation of fractions of T. diversifolia led to the identification of 7 novel hydroxycinnamates; 4-O 1 O caffeoylglucosyl quinic acid, 4 O caffeoyl 2 hydroxy 3 methylbutanoic acid, 4-O-caffeoyl-2-hydroxybutanoic acid, 3,4 dihydroxyphenyl-4-O-caffeoyl-2-hydroxybutanoate, 4-vinylphenyl 4 O caffeoyl 2-hydroxy 3 methylbutanoate, 4 O caffeoyl-caffeoyloxymethyl 2 hydroxy 3 methylbutanoate, 4 O-caffeoyl 2 2 3,4 dihydroxyphenyl acetoyloxy 3-methylbutanoic acid from T. diversifolia leaves that had not been previously reported in nature. Their structures have been assigned based on the unique MS MS fragmentation patterns for each of the compounds in a switching negative or positive ionisation mode and deduction from 1D 1H and 13C NMR of similar compound. In total, 55 phenolic compounds from aqueous fractions of T. diversifolia have been identified including 4 hydroxybenzoic acids, 19 hydroxycinnamic acids, 22 flavonoids, 1 saponin triterpenoid and 9 coumarins and furocoumarins. The present study further showed that the DPPH radical scavenging effect and reducing power antioxidant activity of tested samples of T. diversifolia showed a moderate correlation with the phenolic content present in these samples. This implied that the antioxidant potential was just partly attributed to its phenolic content. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-08
Reservoir rock preoperty and hydrocarbon potentieal in the offshore gamtoos and algoa basins, South Africa
- Authors: Mokoele, Salmina Phuti
- Date: 2022-07
- Subjects: Hydrocarbon reservoirs , South Africa -- Gamtoos River , Gamtoos Estuary (South Africa)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27981 , vital:71409
- Description: Various research methods were employed to evaluate reservoir rock properties and source rock maturity for hydrocarbon potential in the offshore Gamtoos and Algoa basins, including lithostratigraphy, facies analysis, petrography, geophysics, geochemistry and basin modelling. Sedimentary facies were identified in the Gamtoos Basin along with their inferred depositional systems, mainly from the synrift I and II successions. This was also supplemented by lithostratigraphic evaluation of 12 wells across the study area. Facies analysis was applied to describe different rock types with depositional signatures by using the following parameters: grain fabric/texture, primary sedimentary structures, and fossil contents. Different types of lithofacies and biofacies were recorded indicating variations in bioturbation from low to high intensities. The results revealed a total of 15 types of facies from five cores, which were further subdivided into 8 types of sandstones, 3 types of siltstones, 3 types of mudstones and 1 type of conglomerate. Furthermore, five facies associations FA1 to FA5 were recognized from core evaluation: hemipelagite facies association, fine-grained, thinly bedded heterolithic sandstone-mudstone facies association (low-density turbidity flows), medium to coarse grained massive sandstone facies association high-density turbidity flows, debrites hybrid facies association and coarse grained conglomerate facies association. In terms of lithostratigraphic sequence, they correspond with fine- to medium-grained massive sandstone units of the Ta division, horizontal laminated sandstone units of the Tb division, fine to medium grained wavy laminated sandstone units of the Tc division, parallel laminated siltstones intercalated with fine grained ripple and lenticular sandstones of the Tc to Td divisions and fine grained massive, bedded siltstone units of the Te division. Both the Gamtoos and Algoa offshore basins comprise wells with proven source rock presence. Results from geochemical evaluations have revealed the presence of significant quantities of Late Jurassic to Early Cretaceous (Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian) source rock intervals. The wells used for this research intersected a total of 25 source rocks across the various age groups with an average thickness of 70 m. Source rocks with hydrocarbon potentials were intersected at Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian successions. The source rocks indicate good to excellent quality of hydrocarbons with the potential to generate both oil to gas. For example, Tithonian source rock shows a tremendous petroleum generation potential with mostly type II (oil prone) and type II/III (oil to gas prone) kerogen. The data suggests that the Tithonian source rock was mainly deposited in marine depositional settings with planktons being the main source of kerogen. Some of the kerogen could have originated from limited quantities of algae (marine settings) and terrestrial plants. The source rock indicates a potential to generate variable hydrocarbons from oil, wet gas and dry gas. The Kimmeridgian and Tithonian source rocks range from main oil window to post gas mature zone. In the south-eastern part of the offshore Gamtoos Basin, deep marine shale source rocks were deposited between the Kimmeridgian and Tithonian age and these marine conditions continued throughout the synrift stage. The Algoa Basin indicates the deposition of deep-water shale source rocks resulting from a transgression period. The Berriasian source rock indicates a range in maturity from the early oil to gas windows in the Gamtoos graben between 126 Ma and present day. The source rock further shows a maximum transformation ratio of 100 percent at well Ha-D1 in the Gamtoos Basin. The Valanginian source rock indicates a range in maturity from early to late oil windows in the Algoa Basin with extremely low rates of transformation at a maximum of 24.67 percentage at well Hb-B1. The Hauterivian source rock dominantly plots within the early to main oil windows with vitrinite values between 0.6 and 0.8 percent. Results obtained from this research indicate the presence of moderate to good quality source rocks from the Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian. Majority of the source rocks have type III kerogen which is most likely to generate gas. The study area shows the presence of good quality source rocks with good petroleum generation potentials. The source rocks also show the ability to generate and expel hydrocarbons. The deeper sections of the grabens indicate high maturity levels with source rocks dominantly in the gas and late oil windows while the flanks are indicative of lower maturity stages between early and main oil windows. The best source rocks were mainly intersected and modelled from the synrift section while the upper transitional to drift sections indicate good quality reservoir rocks. The upper sections of the study area show a tremendous improvement in the quality of the reservoirs with porosity levels recorded to be up to 26 percent. The porosity levels increase up to 17 percent at well Ha-B2. This generally improved the potential for good reservoirs in the area from what has been intersected by the wells to the entire study area with the presence of effective traps and seals. The influence of hydrothermal alteration and chlorite cementation is quite low at these shallower sequences which further improved the quality of these reservoirs. Some of the sandstones intersected from the synrift sections range from very fine to coarse grained in texture with very low permeability and porosity due to extensive carbonate cementation, and also affected by hydrothermal alteration resulted from the extensive faulting in the area. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-07
- Authors: Mokoele, Salmina Phuti
- Date: 2022-07
- Subjects: Hydrocarbon reservoirs , South Africa -- Gamtoos River , Gamtoos Estuary (South Africa)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27981 , vital:71409
- Description: Various research methods were employed to evaluate reservoir rock properties and source rock maturity for hydrocarbon potential in the offshore Gamtoos and Algoa basins, including lithostratigraphy, facies analysis, petrography, geophysics, geochemistry and basin modelling. Sedimentary facies were identified in the Gamtoos Basin along with their inferred depositional systems, mainly from the synrift I and II successions. This was also supplemented by lithostratigraphic evaluation of 12 wells across the study area. Facies analysis was applied to describe different rock types with depositional signatures by using the following parameters: grain fabric/texture, primary sedimentary structures, and fossil contents. Different types of lithofacies and biofacies were recorded indicating variations in bioturbation from low to high intensities. The results revealed a total of 15 types of facies from five cores, which were further subdivided into 8 types of sandstones, 3 types of siltstones, 3 types of mudstones and 1 type of conglomerate. Furthermore, five facies associations FA1 to FA5 were recognized from core evaluation: hemipelagite facies association, fine-grained, thinly bedded heterolithic sandstone-mudstone facies association (low-density turbidity flows), medium to coarse grained massive sandstone facies association high-density turbidity flows, debrites hybrid facies association and coarse grained conglomerate facies association. In terms of lithostratigraphic sequence, they correspond with fine- to medium-grained massive sandstone units of the Ta division, horizontal laminated sandstone units of the Tb division, fine to medium grained wavy laminated sandstone units of the Tc division, parallel laminated siltstones intercalated with fine grained ripple and lenticular sandstones of the Tc to Td divisions and fine grained massive, bedded siltstone units of the Te division. Both the Gamtoos and Algoa offshore basins comprise wells with proven source rock presence. Results from geochemical evaluations have revealed the presence of significant quantities of Late Jurassic to Early Cretaceous (Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian) source rock intervals. The wells used for this research intersected a total of 25 source rocks across the various age groups with an average thickness of 70 m. Source rocks with hydrocarbon potentials were intersected at Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian successions. The source rocks indicate good to excellent quality of hydrocarbons with the potential to generate both oil to gas. For example, Tithonian source rock shows a tremendous petroleum generation potential with mostly type II (oil prone) and type II/III (oil to gas prone) kerogen. The data suggests that the Tithonian source rock was mainly deposited in marine depositional settings with planktons being the main source of kerogen. Some of the kerogen could have originated from limited quantities of algae (marine settings) and terrestrial plants. The source rock indicates a potential to generate variable hydrocarbons from oil, wet gas and dry gas. The Kimmeridgian and Tithonian source rocks range from main oil window to post gas mature zone. In the south-eastern part of the offshore Gamtoos Basin, deep marine shale source rocks were deposited between the Kimmeridgian and Tithonian age and these marine conditions continued throughout the synrift stage. The Algoa Basin indicates the deposition of deep-water shale source rocks resulting from a transgression period. The Berriasian source rock indicates a range in maturity from the early oil to gas windows in the Gamtoos graben between 126 Ma and present day. The source rock further shows a maximum transformation ratio of 100 percent at well Ha-D1 in the Gamtoos Basin. The Valanginian source rock indicates a range in maturity from early to late oil windows in the Algoa Basin with extremely low rates of transformation at a maximum of 24.67 percentage at well Hb-B1. The Hauterivian source rock dominantly plots within the early to main oil windows with vitrinite values between 0.6 and 0.8 percent. Results obtained from this research indicate the presence of moderate to good quality source rocks from the Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian. Majority of the source rocks have type III kerogen which is most likely to generate gas. The study area shows the presence of good quality source rocks with good petroleum generation potentials. The source rocks also show the ability to generate and expel hydrocarbons. The deeper sections of the grabens indicate high maturity levels with source rocks dominantly in the gas and late oil windows while the flanks are indicative of lower maturity stages between early and main oil windows. The best source rocks were mainly intersected and modelled from the synrift section while the upper transitional to drift sections indicate good quality reservoir rocks. The upper sections of the study area show a tremendous improvement in the quality of the reservoirs with porosity levels recorded to be up to 26 percent. The porosity levels increase up to 17 percent at well Ha-B2. This generally improved the potential for good reservoirs in the area from what has been intersected by the wells to the entire study area with the presence of effective traps and seals. The influence of hydrothermal alteration and chlorite cementation is quite low at these shallower sequences which further improved the quality of these reservoirs. Some of the sandstones intersected from the synrift sections range from very fine to coarse grained in texture with very low permeability and porosity due to extensive carbonate cementation, and also affected by hydrothermal alteration resulted from the extensive faulting in the area. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-07
Effect of pomegranate (Punica granatum L) peel powder meal on growth performance, gut integrity, haemato-biochemical indices, meat, and bone quality of broiler chickens
- Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of antimicrobial combination therapy options for the management of integron-mediated multidrug resistance in enterococcus species and acinetobacter baumannii from aquatic environment in the Eastern Cape Province, South Africa
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of groundwater potential using geological and geophysical methods in the University of Fort Hare Alice Campus, Eastern Cape Province of South Africa
- Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Pharmacological, toxicological and phytochemical evaluation of helichrysum petiolare hilliard & b.l. burtt - an indigenous plant traditionally used in the treatment of diabetes in the eastern cape province of South Africa
- Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
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- Date Issued: 2022-04