An experiment was conducted to investigate the effect of dietary chromium picolinate supplement on growth and haematology parameters of grass carp, Ctenopharyngodon idellus. Six diets with increasing dietary chromium picolinate levels 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg kg(-1) were fed to triplicate groups of 20 fish (initial weight of 12.78 +/- 1.16 g, mean +/- SD) in a flow water system for 10 weeks. Fish fed the diet supplemented with 0.8 mg Cr kg(-1) had significantly improved weight gain (WG), feed efficiency ratio (FER), protein efficiency ratio (PER) and protein retention (PR). Fish fed high-chromium diets exhibited lower whole-body crude lipid contents than fish fed low-chromium diets. Liver glycogen concentrations for fish fed the diet with 0.2 mg Cr kg(-1) was the highest (77.67 mg g(-1)). Fish fed the diet supplemented with 1.6 and 3.2 mg Cr kg(-1) had significantly lower liver glycogen concentrations than other groups (P < 0.05). The highest serum insulin concentrations were observed in fish fed the diet supplemented with 0.8 mg Cr kg(-1), but serum insulin concentrations decreased (P < 0.05) when dietary supplementation of chromium was higher than 0.8 mg Cr kg(-1). Cholesterol concentrations decreased in direct proportion to dietary chromium level and achieved the lowest level when the fish were fed the 0.8 mg Cr kg(-1) diet, but increased when the fish were fed the diet with more than 0.8 mg Cr kg(-1) (P < 0.05). Fish fed the diet supplemented with 0.8 mg Cr kg(-1) had higher triglyceride and high-density lipoprotein cholesterol (HDL-C) concentrations compared to other treatments. The results of the present study suggested that chromium picolinate could modify serum carbohydrate and lipid metabolism profile, and that the optimal dietary chromium level was 0.8 mg kg(-1) for grass carp according to growth.

A 10-week feeding trial was conducted to investigate the beneficial effects of bile acids (BAs) on hepatic health status in tongue sole (Cynoglossus semilaevis). Three experimental diets were prepared with different levels of BA inclusion in the commercial basal diet: control group (CT: 0 mg/kg basal diet), low-level group (BA1: 300 mg/kg basal diet), and high-level group (900 mg/kg basal diet). At the end of the feeding trial, growth performance and survival rate were measured, as well as numerous physiological and biochemical parameters of the liver, including four hepatic function indices, five antioxidant indices, five lipid metabolism parameters, and three digestive enzyme activities. Moreover, the mRNA expression levels of three growth-related genes and three immune-related genes in the liver were assayed. Results showed that growth performance and survival were substantially improved in both low- and high-level BA inclusive groups. Further, the tested liver physiological and biochemical parameters combined with the quantitative real-time PCR results revealed enhanced antioxidant capacity, energy metabolism, digestive ability, and immune response. Finally, these findings provide a wider spectrum of the beneficial effects of dietary BAs on liver health in tongue sole.