Study On The Histology And Histochemistry Of Digestive Tract In Brachymystax Lenok Larvae

Although it is a high quality economical species,the study of compound feed for the Brachymystax lenok was unsuitably superficial.There is no study about histology of the digestive system and the digestive enzyme of the fish as well as the digestive ability. We mastered the fish digestive enzyme activity and changes to help to understand the different components of fish food digestion, enriched and improved varieties of basic breeding biology and nutrition information for the preparation of high-quality artificial diet and establishment of fish suitable breeding conditions for the provision of basic data by this study which were to investigate the structure of digestive tract and distribution of digestive enzymes,It guided the aquaculture industry in the food problem for the aquaculture industry to create an entirely new situation.So we evolved this experiment,the description of results and discussion as follows:In Exp.1, the histological structure of stomach, intestine were observed with larvae post-hatch for 40d feeding living organism. Histological results showed that intact structure of intestinal villus has formed for digestive nutrients and extended into lumen to enhance efficiency for digestion and absorption through sufficient contact with chymus. There are no found nutrients in storage sites after digestion,which illustrated the capacity of intestinal cells have not yet reached the saturation transfer. Anterior segments of intestinal become thinner,the longer villi be able to fully extending, ensured the inter-villous with chyme full contact,improved the efficiency of digestion and absorption of the structure of protection. Posterior segments of intestinal become thicker related with increasing movement of chymus and formation of feces.So it can be concluded that the intestinal have maturated. The nutrient digestioning and absorptioning are no good because of gastric function imperfect. The stomach has complete mucosal layers, with the secretion of functional structure. This development status is similar to the majority of juvenile fish. Pyloric caeca were found,it is very important to digestioning. It shows that the initial degradation process of the food has reached the level of juvenile fish.In Exp.2,Histochemical distribution of digestive enzymes revealed that there have been enzymes activities, including acid phosphatase, alkaline phosphatase, non-specific esterase, esterase and phopholipidase A2, along with intestine. Alkaline phosphatase, acid phosphatase are distributed throughout the intestine, Non-specific esterase, esterase and phospholipase A2 are found in the anterior intestine,also esterase is found in the midintestine.The activities of digestive enzymes were mainly distributed in anterior segments and play a crucial role in digestion of nutrients, but that of posterior segments were weaker compared with anterior parts. Presence of acid phosphatase implied that endogenous digestion also play an important role of digestion in larvae.