Effects of different chromium sources on growth performance, serum biochemical, hepatopancreas glycometabolism enzymes activities, IR, GLUT2 and SGLT1 gene expression of common carp ( Cyprinus carpio )

Abstract

A 60-day feeding trial was conducted to evaluate the effects of different chromium sources on the common carp. Four diets (32.2% crude protein and 6% lipids of dry matter) were formulated to add chromium oxide (Cr2O3), chromium picolinate (CrPic) and chromium methionine (CrMet) with 2 mg/kg Cr3+, respectively, and one basal diet. Each diet was randomly assigned to triplicate groups of 60 juvenile common carp (approximately 40.95 ± 4.80 g). The results indicated that fish fed CrMet diets had significantly higher weight gain, specific growth rate and feed efficiency than other groups (p < 0.05). No significant differences in the whole body compositions except the lipid content significantly increased in CrMet diets (p < 0.05). Fish that were fed chromium diets had significantly higher lactic dehydrogenase and creatine kinase in serum, succinic acid dehydrogenase and lactic acid in muscle, pyruvate kinase and glycogen synthase in hepatopancreas, lower glucose concentration and phosphoenolpyruvate carboxykinase activities in hepatopancreas than those given the basal diet (p < 0.05). Insulin receptor (IR) in serum, IR gene expression in hepatopancreas and sodium-dependent glucose transporter 1 (SGLT1) in intestinal was increased (p < 0.05), while the cortisol decreased significantly in the dietary of CrMet or CrPic (p < 0.05). CrMet supplementation also increased HK activities, up-regulated glucose transporter 2 (GLUT2) in hepatopancreas (p < 0.05). In conclusion, dietary addition of CrMet improved growth performance, adjusted glycometabolism enzyme activities, IR, GLUT2 and SGLT1 gene expression and had a significant impact on the carbohydrate utilization of juvenile common carp fed high corn diets compared with CrPic and Cr2O3.