Effect of bile acids on growth and body composition of cobia (Rachycentron canadum).

To study the effect of bile acids on the growth performance and body compositon of cobia (Rachycentron canadum),we added four levels of bile acids (0,0.015%,0.03% and 0.045%) to four iso-energetic and iso-nitrogenous practical diets.The cobia with an initial wet weight of (5.4±0.12) g was fed for 8 weeks,and its weight gain rate (WGR,%),special growth rate (SGR,%),feed conversion rate (FCR) and liver and serum were analyzed.The results show that the WGR of 0.03% group is significantly higher than that of the control group and 0.015% group (P0.05),and the FCR is significantly lower than those two groups.The cholesterol in serum and the fat content of liver show a negative correlation with the bile acids amount in diets.There is no significant difference among the survival rate,SGR,ash and moisture in the whole fish body and meal.The results indicate that adding bile acid to diet can promote the growth of cobia and reduce the accumulation of body lipid.