Growing Development Characteristics On The Digestive Tract And Histology And Histochemistry Of Wild And Cultivated Sparus Latus

To understand about morphology and histology of yellowfin black porgy (Sparus latus), and promote studies on base biology, digestion physiology, nutrition and feed, anatomy, light microscopes and histochemical technique were used in this dissertation to investigate the morphology and histology of the digestive tract of larvae, juvenile and young yellowfin black porgy. Meanwhile, the morphological and histological study on the digestive tract of wild and cultivated yellowfin black porgy were investigated, the types and distribution of mucous cells in the alimentary canal and taste buds were compared. The results showed as follows:1. Morphological and histological study on the digestive tract of larvae, juvenile and young yellowfin black porgy (Sparus latus)The morphology and histology of the digestive tract of larvae, juvenile and young yellowfin black porgy (Sparus latus) has been studied using routine method of paraffin tissue section. The results showed that:on the2nd day after hatching, the digestive tract was an undifferentiated canal. The digestive tract of5-day old larva was divided into esophagus, stomach and intestinal tract, the esophagus’epithelium made up with cubic cells, the epithelium of stomach consisted of single low columnar cells, and they neither had mucosal fold. The intestinal tract differentiated small gut and rectum, small gut had mucosal folds, and rectum had no mucosal fold. The digestive tract of7-day old larva differentiated further, the walls were thicker, esophagus and stomach had no mucosal folds, the pyloric caeca were found, and the goblet cells in small intestine were abundant. The digestive canal of juvenile grew into young qualitatively, esophagus, stomach, pyloric caecum and intestinal tract showed up innate type and numbers. The digestive tract was expanded, muscularis was extruded, mucosal folds were deepened, and goblet cells were increased. The digestive tract of young developed more perfectly, its histology structure was similar to adult, which consisted of mucous membrane, submucosa, muscularis and serous membrane from inner to outer. It could be concluded that the characteristics of post embryonic development of digestive tract were corresponded to ingestive way and function.2. Morphological and histological study on the digestive tract of wild and cultivated yellow fin black porgy(Sparus latus)The morphology and histology of the digestive tract of wild and cultivated yellowfin black porgy(Sparus latus) were studied using routine method of paraffin tissue section. The results showed that there were some differences between the populations. Morphological observations showed that oesophagus was crude and short, and the V-shaped stomach was divided into three portions:cardiac stomach, fundic stomach and pyloric stomach. There were four pyloric caeca, and intestine was detoured two inflections in the body cavity. In wild fish, the teeth were harder and sharper, the fat in the body cavity was less, and the digestive tract was cruder and shorter. The average intestinal coefficients of the wild and cultivated yellowfin black porgy were0.71±0.03and0.94±0.12, respectively. Histological observations showed that mucous epithelium of oesophagus was composed of pinacocyte layer and goblet cell layer with rich goblet cells. Stomach had a single-layered columnar epithelium, without goblet cell. The gastric gland was developed in the cardiac stomach and fundic stomach. The histological features of pyloric caeca were similar to those of small intestine, with columnar epithelium and less goblet cells. Meanwhile the distribution trend of goblet cell in the whole small intestine was:foregut>midgut> hindgut and cultivated fish>wild fish. There were more goblet cells in rectum than in small intestine. The major histological differences between wild and cultivated yellowfin black porgy were that there were more goblet cells in the same part of digestive tract in cultivated fish than in wild fish, while the muscular coat was thicker in wild fish than in cultivated fish. It could be concluded that the differences of digestive tract between the two populations relied on their living condition and foods. 3. Types and distribution of mucous cells in the digestive tracts of wild and cultivated yellowfin black porgy (Sparus lotus)The types and distribution of mucous cells in the digestive tract of wild and cultivated yellowfin black porgy (Sparus latus) have been studied using routine method of paraffin tissue section and AB-PAS staining method, and4types of the mucous cells in the digestive tracts were observed. Type Ⅰ was pure red, PAS positive containing neutral mucoitin. Type Ⅱ was pure blue, PAS negative containing acidic mucoitin. Type Ⅲ was purple reddish, PAS positive more than AB containing mainly neutral mucoitin and a few acidic mucoitin. TypeⅣ was blue purple, AB positive more than PAS containing mainly acidic mucoitin and a few neutral mucoitin.The mucous cells were distributed in every part of the alimentary canal of yellowfin black porgy, however, the cell types and cell distribution vary at different sections. Mucous cells in the esophagus gave priority to type Ⅰ and Ⅱ, the cardiac stomach and fundic stomach had type Ⅰ and Ⅱ, the pyloric stomach had type Ⅰ, and type Ⅱ was the most in the pyloric caeca, small intestine and rectum. The difference of wild and cultivated yellowfin black porgy was that the numbers of mucous cells in the wild fish were more than the cultivated fish in the same part of digestive tract. It could be concluded that the types and distribution of mucous cells in the digestive tract between the two populations relied on their living condition and food, and probably, it also related to the distribution of flora.4. Histological study on the taste buds of wild and cultivated yellowfin black porgy (Sparus latus)The histology of the taste buds of wild and cultivated yellowfin black porgy (Sparus latus) were studied using routine method of paraffin tissue section. The results showed that the organizational structure of taste buds of wild and cultivated fish were same, they were oval and constituted with taste cells, supporting cells and basal cells. There were taste buds in the epitheliums of lip, oral mucosa, tongue, pharynx and gill arch. The number of taste buds:pharynx> gill arch>tongue> oral mucosa>lip. There were more taste buds in the same section in wild fish than cultivated fish, it was corresponded to their living condition and function.