Antimicrobial peptides have attracted considerable attention because of their potential use for therapy and prophylaxis. We evaluated the effects of dietary supplementation with recombinant antimicrobial peptide on growth, immunity, and performance in the protest test in 10.68g±0.53g. The fish were divided into six treatment groups and fed experimental diets containing cell numbers, and catalase activity were significantly higher in the groups supplemented with 5 and 10 mg/kg compared with the control. The specific growth rate was highest in the group given 5 mg/kg RAP. Liver lysozyme activity were significantly lower in the group given 50 mg/kg RAP than in the control. Supplementation with 100 mg/kg florfenicol increased the number of red blood cells, but had no effect on the other indexes. Following infection with , the death rate was significantly lower in groups fed between 5–20 mg/kg RAP than in the control. The survival was highest in the group fed 5 mg/kg. Our results suggest that dietary supplementation with appropriate levels of antimicrobial peptide improves growth, immunity, and performance in the protest test . However, increasing the dose can lead to negative effects on growth and enzyme activity. Therefore, we recommend that supplementation should not exceed 20 mg/kg. Our results provide insight into the proper application of recombinant antimicrobial peptides to