- Title
- Morphology and histochemistry of the digestive tract in the Banded Tilapia (Tilapia Sparrmanii, Smith 1840)
- Creator
- Bongile, Bhomela
- Subject
- Tilapia sparrmanii, fish; Tilapia; teleost; stomach; digestive system; light microscopy; light microscopy; histology; morphology Teleostei, digestive tube, histology
- Date
- 2014
- Type
- Masters, Msc Zoology
- Identifier
- http://hdl.handle.net/11260/2401
- Identifier
- vital:41456
- Description
- The digestive system of Tilapia sparrmanii, Smith 1894, a small sized cichlid fish widely distributed in Southern Africa and of little economic importance was studied by light microscopy as part of establishing base-line data for future references. The gut in T. sparrmanii was a simple long coiled tube. With greater fish length, the gut progressed into a complexly-coiled definitive form. Strong linear correlations were observed between fish size and gut length. The esophagus was relatively very short and the stomach sac-like and small. Histologically, T. sparrmanii displayed a stratified esophagus epithelium with goblet cells which displayed both neutral and acid mucus at the anterior region. The stomach of T. sparrmanii was divided into three distinct segments the cardiac, fundic, and pyloric portions. The study revealed that the gastric wall is composed of several tunicae: mucosa, submucosa, muscularis and serosa. The tunica mucosa was thrown up into a number of high longitudinal folds projecting into a lumen. The mucosal surface had surface epithelial cells. The epithelium in this region was simple columnar devoid of goblet cells, with glandular regions in the lamina propria. The mucosa of the fundic region had gastric pits lined by columnar epithelium, and simple tubular glands filled most of the lamina propria. The pyloric part of the stomach was very short and its mucosa was slightly folded and devoid of both gastric pits and mucous glandular cells. The lining epithelium of this portion of the stomach was simple columnar and a few goblet cells were seen at its junction with the first part of the intestine. The tunica muscularis of the stomach contained skeletal muscle in the initial and terminal regions, usually intermingled with smooth muscle fibres. Skeletal muscle fibres were also observed in the first portion of the proximal intestine, iii near the junction with the stomach. Gastric pits were present as invaginations of the mucosal surface. Their epithelium secreted both neutral and acid mucins. Simple, straight, tubular unbranched gastric glands occupied most of the surface of the mucosa, and were lined with cells that had eosinophilic granules. The tunica muscularis of the stomach consisted of skeletal muscles usually mixed with smooth muscle fibres. Also, the stomach was separated from the proximal intestine by a pyloric sphincter. Results demonstrate that the intestine was a relatively undifferentiated muscular tube lined with a simple columnar epithelium interspersed with goblet cells. The proximal region had a greater surface area, as revealed by the presence of elongated mucosal ridges. The enterocytes were covered apically with uniform microvilli. The number of goblet cells were moderate in the proximal intestine and fewer in the medial intestine. All segments of the intestine contained neutral and acidic mucins. The distal intestine mucosa was thinner and less elaborately folded and consisted of columnar cells with shorter and sparser microvilli. After the intestinerectal valve, the rectum displayed lower mucosal folds, numerous goblet cells and a thicker muscularis. An ileorectal valve was observed. This confirms that separate intestine and rectum does exist in T. sparrmanii.
- Format
- Publisher
- Walter Sisulu University
- Language
- English
- Rights
- Walter Sisulu University
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WSU Department of Biological and Environmental Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | BHOMELA MSc DISSERTATION .pdf | 1010 KB | Adobe Acrobat PDF | View Details Download |