anatomical study of the digestive tract of grass carp (ctenopharyngodon idella)

due to manual feeding of grass carps in aquaculture, digestion problems in this specie are developing. diagnosing and treating these diseases require a good knowledge of anatomy of digestive tract and its appendixes. the goal of this research is getting acquinted with different parts of grass carps’ digestive tract and their relationship. for this purpose, twenty grass carps were used. first the digestive tract’s anatomy was examined macrospically using loop. for measuring the diameter of different parts in digestive tracts, a digital caliper was used and the results were analyzed with spss 16 software and pair sample t method. the results showed a distension at the end of esophagus which was called crop. mucosal folds at the end of esophagus resembles a plexus and changed into linear form at the end. the intestine’s diameter decreases gradually to a certain point and then becomes steady. the mucosal folds of intestine are transverse and parallel and these folds were longitudinal at the cloac. there was no valve or sphincter in the digestive tract. generally it can be concluded that the morphology of the digestive tract in carps has unique specifications and further studies are needed for a recognizing them.