An 8-week feeding trial was conducted to determine the optimal dietary protein level for juvenile marbled flounder.Five semi-purified test diets were formulated to contain different protein levels(CP)including 42.7%,4...An 8-week feeding trial was conducted to determine the optimal dietary protein level for juvenile marbled flounder.Five semi-purified test diets were formulated to contain different protein levels(CP)including 42.7%,47.4%,53.3%,58.8%,and 64.5%(dry matter),named as CP42.7,CP47.4,CP53.3,CP58.8,and CP64.5,respectively.Five hundred and twenty-five juveniles(6.0±0.1 g)were randomly distributed into 15 tanks(300 L tanks),resulting in 35 fish per tank(n-3 tanks).Fish were fed the test diets 5 times per day until satiation.The CP58.8 resulted in the highest gain in weight and the best efficiency in feed utilization among the tested protein levels(P<0.05).Fish fed the CP58.8 diet showed significantly higher whole-body protein and lipid contents than the fish that were fed the other diets(P<0.05).Fish fed the CP53.3,CP58.8,and CP64.5 diets showed a significantly higher dorsal-muscle lipid content than the fish that were fed the CP42.7 and CP47.4 diets(P<0.05).The one-slope straight broken-line regression analysis on the results of the thermal growth coefficient and feed conversion ratio indicated that the estimated optimum dietary protein level was 58.8%.Taken together,it is suggested that the dietary protein level of 58.8%is optimal for better growth and high efficiency in feed utilization for the juvenile marbled flounder.展开更多
基金This work was supported by a grant from the National Institute of Fisheries Science(R2021040).
文摘An 8-week feeding trial was conducted to determine the optimal dietary protein level for juvenile marbled flounder.Five semi-purified test diets were formulated to contain different protein levels(CP)including 42.7%,47.4%,53.3%,58.8%,and 64.5%(dry matter),named as CP42.7,CP47.4,CP53.3,CP58.8,and CP64.5,respectively.Five hundred and twenty-five juveniles(6.0±0.1 g)were randomly distributed into 15 tanks(300 L tanks),resulting in 35 fish per tank(n-3 tanks).Fish were fed the test diets 5 times per day until satiation.The CP58.8 resulted in the highest gain in weight and the best efficiency in feed utilization among the tested protein levels(P<0.05).Fish fed the CP58.8 diet showed significantly higher whole-body protein and lipid contents than the fish that were fed the other diets(P<0.05).Fish fed the CP53.3,CP58.8,and CP64.5 diets showed a significantly higher dorsal-muscle lipid content than the fish that were fed the CP42.7 and CP47.4 diets(P<0.05).The one-slope straight broken-line regression analysis on the results of the thermal growth coefficient and feed conversion ratio indicated that the estimated optimum dietary protein level was 58.8%.Taken together,it is suggested that the dietary protein level of 58.8%is optimal for better growth and high efficiency in feed utilization for the juvenile marbled flounder.
