Abstract：Juvenile Kunming schizothoracin Schizothorax graham with initial body weight of (25 .97 ± 9 .29) g were randomly divided into 6 groups at a rate of 10 fish per group and fed diets containing niacin of 15 .5(control group) ,28 .671 ,38 .516 ,68 .685 ,81 .608 ,and 99 .568 mg/kg at a feeding rate of 2% -5%for 10 weeks .Condition factor ,weight gain rate ,specific growth rate ,and hepatopancreas index ,and intestinal index were measured to evaluate the optimal dietary requirement of niacin .The results showed that the specific growth rate and the weight gain rate were found to be first increased and then decreased with the increase in dietary nicotinic acid content , the maximum (144 .788% in weight gain , and 1 .24336% /d in specific growth rate ) in 38 .516 mg/kg group . The maximal condition factors and hepatopancreas indexes were observed in the 28 .617 and 38 .516 mg/kg groups ,significantly higher than those in the control group (P<0 .05) .In other groups ,however ,the hepatopancreas indexes were found significantly lower than that in the control group (P<0 .05) .There was survival rate of 100% in each group ,and the hemoglobin in each groups were no significant difference (P>0 .05) ,which is attributed to the fact that the nicotinic acid content in the control diet meets the normal demand .In this experiment ,the optimal dietary nicotinic acid level of juvenile Kunming schizothoracin is of 36 .83 mg/kg based on the specific grow th rate .
