The object of this study was to evaluate the effects of dietary carbohydrate-to-lipid (CHO:L) ratios on growth performance,body composition,digestive activities and glycolysis of juvenile Jian carp (Cyprinus carpio var.jian).Fish were fed six isonitrogenous and isoenergetic diets with different (CHO:L) ratios (2.3,3.0,4.0,5.6,7.7,12.1) three times daily for 8 weeks.The results indicated that weight gain rate (WGR),specific growth rate (SGR),protein efficiency ratio (PER) and nitrogen retention efficiency (NRE) increased significantly (P<0.05) when dietary CHO:L increased from 2.3 to 7.7,and then they nonsignificantly decreased (P>0.05) as dietary CHO:L ratios increased from 7.7 to 12.1,while feed conversion ratio (FCR) showed the opposite variation trend.The values of viscerosomatic index (VSI) increased significantly (P<0.05) as dietary CHO:L ratios decreased,so as the whole body,carcass and liver lipid.There were no significant differences in whole body,carcass and liver crude protein among dietary treatments (P>0.05).Intestine amylase activities increased significantly (P<0.05) as dietary CHO:L ratios increased,whereas intestine lipase activities increased significantly (P<0.05) as dietary CHO:L ratios decreased.Liver glycogen,blood glucose and insulin increased significantly (P<0.05) as CHO:L ratios increased.Activities of glucokinase and pyruvate kinase were stimulated significantly (P<0.05) by elevated levels of dietary carbohydrate.However,plasma total cholesterol and triacylglyceride levels increased linearly as dietary CHO:L ratios decreased(P<0.05).Based on a second-order polynomial regression analysis of WGR against dietary CHO:L ratios,corresponding to a CHO:L ratio of 8.14,a diet holding 350 g/kg of crude protein and 13.2 MJ/kg of digestive energy,proved to be optimal for juvenile Jian carp.These results demonstrated that utilization of dietary lipid and carbohydrate was moderate in juvenile Jian carp,but the fish was a little more capable of utilizing carbohydrate compared with lipid.