Effects of dietary shrimp protein-peptides on growth performance and antioxidant indices of juvenile Epinephelus lanceolatus×E. fuscoguttatuss under two dietary protein levels

To investigate the effects of dietary shrimp protein-peptides（ SPP） on growth performance and antioxidant indices of juvenile Epinephelus lanceolatus×E. fuscoguttatuss under two dietary protein levels，six diets were formulated to contain two crude protein（ CP） concentrations（ 440 g/kg and 440 g/kg） and three SPP levels （0 g/kg，10 g/kg and 20 g/kg）. Each diet was randomly assigned to triplicate treatments of 20 fishes for 8 weeks， and the initial body weight of fish was 13.67（±0.11）g. The results indicated that when the dietary protein concentration was the same，the final body weight（ FBW） and weight gain rate（ WGR） significantly increased with SPP level increasing to 10 g/kg，beyond which a decrease was observed. When the SPP level was the same，FBW and WG of 480 g/kg CP group were significantly higher than those of 440 g/kg CP group. The change trends of protein efficiency ratio，muscle crude protein and crude fat contents，serum AST and ALT activities，hepatic CAT and T-AOC activities were similar with WGR. Meanwhile，the change trends of feed conversion ratio，serum glucose content and liver MDA content were the opposite with WGR. In summary，adding SPP in diets containing different protein concentrations could promote the growth performance of juvenile E. lanceolatus×E. fuscoguttatuss，and increase its antioxidant capacity，but adding too high level of SPP would cause inhibition. Therefore，the suitable SPP level was is 10 g/kg.