Effects of dietary bile acid on growth performance, fatty enzymatic activities and biochemical indices of turbot Scophthalmus maximus L. junveniles

Abstract:

In order to investigate the effects of dietary bile acid on growth, body composition, fatty enzymatic activities and biochemical indices of turbot Scophthalmus maximus L. juveniles, five isonitrogen and isocaloric diets containing graded levels of bile acid(0.00%, 0.03%, 0.06%, 0.09%, and 0.12% of dry matter) were formulated(named D1, D2, D3, D4, and D5, D5 as control group). Each diet was assigned to triplicate tanks of turbot juveniles with initial body weight 26.5 g for 56 days. The results showed that:(1) Growth performance and figure indices were increased by dietary bile acid, and indices of D3, D4, D5 groups were significantly higher than D1 group, but there were no differences among them.(2) Crude lipid and crude ash contents of whole fish were decreased, while crude protein increased by dietary bile acid; Crude lipid of muscle decreased, while crude protein and crude ash increased.(3) Lipase and lipoprotein lipase activities increased at first and kept stable then, but hepatic lipase activities kept increasing.(4) Alanine aminotransferase and asparate aminotransferase activities were decreased while alkaline phosphatase activity was increased by dietary bile acid; total protein and albumin contents increased while triglyceride, total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol decreased by dietary bile acid.(5) Cumulative mortalities of D3, D4 and D5 groups were significantly lower than that of D1 group after being infected with Vibrio anguillarum for 48 hours. With WGR as evaluation indicator, broken-line regression analysis showed that the optimum dietary bile acid of turbot with body weight 26.5 g was 0.09%.