Abstract:This experiment was conducted to examine the effect of high lipid diet on the intestinal structure and lipid metabolism enzymes in juvenile Schizothorax prenanti treated with bile acid. In our study, a total of 360 juvenile S. prenanti, with average body weight of (12.74±0.14) g, were randomly distributed into four groups with three replicates each. The high lipid diet diets with different bile acid levels (0, 75, 150 and 300 mg/kg) were fed to juvenile S. prenanti for 70 days. The results showed that the foregut and midgut intestinal tube wall thickness, as well as villi length significantly increased with increasing dietary bile acid levels up to 75 mg/kg diet, and remained nearly constant thereafter. Meanwhile, the foregut plica width was significantly reduced with increasing dietary bile acid levels up to 75 mg/kg diet, where the response reached a plateau. In addition, we found that the intestinal lipase (LPS), lipoprotein lipase (LPL), hepatic lipase (HL) and total lipase (TL) increased firstly and then tended to stabilize. Interestingly, the activities of LPS and LPL of juvenile S. prenanti were the highest for fish fed with diet containing 300 mg/kg bile acid diet, which were 2881.17 U/g and 14.43 U/mg prot, respectively. While the activities of HL and TL were highest for fish fed 150 mg bile acid/kg diet, which were 43.70 and 58.03 U/mg prot, respectively. Collectively, the results indicated that 75-150 mg bile acid/kg diet can improve the fat metabolism enzyme activity, promote the utiligation of diet lipid and improve intestinal structure, and protect the intestinal health in juvenile S. prenanti.