During endogenous feeding phase,differentiation of the digestive tract was an asynchronous and very intense phenomenon,proceeding from the distal to the proximal part.At hatching,the digestive tract was represented by a gastric cavity filled with yolk and partially differentiated hindgut,and did not communicate with the exterior as the mouth and anus were not yet opened.Along with the yolk sac absorption,stomach and duodenum,were differentiated 3 days post hatch,respectively.By 8-9 days post hatch,the glandular stomach(cardiac region) was developed,meanwhile there was marked differentiation in duodenum and liver.It suggested a functional alimentary canal was developed.But if the initial feeding time was 12 days post hatch,digestive tract developed hardly.If starved to 24-25 d,digestive system of trial fish was retrograded.The alimentary canal seemed shorter and thinner;Cells of gastric gland decreased and became shrunken;Muscle fiber of stomach turned to loosened,under light microscope.Furthermore,intestine columnar epithelium became lowered and microvilli ruptured histologically.The structure of liver was broken,such as ligature of hepatic cells became ruptured,nucleolus of hepatic cells destroyed,and there were no bounds among hepatic cells.