Effects of Dietary Astaxanthin on Growth Performance, Hepatic Antioxidative Activity, hsp70, and HIF-1α Gene Expression of Juvenile Golden Pompano (Trachinotus ovatus)

The present study was conducted to investigate the effects of different astaxanthin (AST) levels on growth performance, hepatic antioxidative activity, heat shock protein 70 (hsp70), and hypoxia-inducible factor-1 alpha (HIF-1α) gene expression of juvenile golden pompano. Fish (mean initial body weight 5.8±0.05g) were fed six isonitrogenous and isoenergetic diets (AST-0, AST-0.005, AST-0.01, AST-0.05, AST-0.1, AST-0.2) containing various supplemented levels of astaxanthin (0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, respectively) in triplicate for 8 weeks. Growth performance (final body weight, FBW; weight gain, WG), and survival of fish fed diets containing astaxanthin above 0.01% were significantly higher (P<0.05) than of fish fed AST-0 and AST-0.005 diets; feed conversion ratio (FCR) showed the opposite trend (P<0.05). Fish fed 0.01% astaxanthin diet showed the highest value of survival. Hepatic antioxidant status (total antioxidant status, TAS; superoxide dismutase, SOD; carbonyl protein content) of shrimp improved significantly when dietary astaxanthin was over 0.01%. Relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA increased with increased dietary astaxanthin levels. The relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA of shrimp fed diets containing astaxanthin above 0.01% were obviously higher than those of shrimp fed AST-0 and AST-0.005 diets. Linear regression analysis on WG and HIF-1a mRNA indicated that the optimum dietary AST levels for optimal growth and immunity of juvenile pompano were 0.011% and 0.013%, respectively.