Abstract:In order to estimate the dietary Zn requirement of blunt snout bream(Megalobrama amblycephal),Five experimental diets containing different Zn contents of 0,68,137,206,275 mg/kg(total Zn of feed was 22.85,98.07,164.00,235.43,307.96 mg/kg)were for mulated with ZnSO4·H2O as the Zn source.A total of 400 blunt snout bream with an initial body weight of 50 g were randomly divided into 5 groups with 4 replicates per group and 20 blunt snout bream per replicate.Each group of fish was fed two diet for 43 days.The results showed as follows:Through regression analysis of relationship between the amount of Zn added to feed,the total Zn of the feed and the SGR,FCR,protein deposition rate,fat deposition rate of the blunt snout bream,when the Zn supplement in the feed was 155.86-161.25 mg/kg(the actual Zn content was 184.85-190.39 mg/kg),blunt snout bream has the best growth performance.In this experiment,the daily feed intake of blunt snout bream was 5.12 g/100 g body weight/d,so the added Zn content of the feed in the 0.798-0.825 mg/100 g weight/d(the total Zn content of the feed was 0.946-0.974 mg/100 g weight/d),blunt snout bream can achieve the maximum growth.The survival rate,fatness,viscera index,scale weight/body weight,body weight/body length,vertebral bone weight/body weight were not significantly affected by dietary Zn content(P>0.05).But in the 0 mg/kg group,vertebral bone length/body length was significantly lower than the 137 mg/kg group(P<0.05);Supplement of Zn is conducive to the growth of the spine of blunt snout bream.