EFFECTS OF STICKWATER ON BILE ACID AND LIPID METABOLISM OF YELLOW CATFISH (PELTEOBAGRUS FULVIDRACO)

To explore effects of stickwater (SW) on bile acid metabolism, 4 isonitrogenous and isoenergetic diets including the control diet containing 30% fish meal (FM) and three experimental diets without fish meal but with 8% (SW8), 17% (SW17), 25% (SW25) stickwater (dry matter) were fromulated to feed the yellow catfish with the initial body weight of (15.67±0.11) g for 60 days in pond cage farming. Compared with FM group, fat content of whole fish of SW25 group decreased observably (P<0.05), and liver fat content of SW17 and SW25 group reduced significantly (P<0.05); Cholesterol in serum of SW17 and SW25 groups decreased from 11.9% to 16.6%, and triglyceride decreased from 32.5% to 47.9% (P<0.05). Liver bile acid of SW25 group decreased by 76.3% (P<0.05) compared with FM group, but serum and intestine bile acid increased by 125.7% and 123.3% (P<0.05). The liver CYP7A1 at mRNA level had no significant difference among five groups, but the expression of BSEP, ABCC4, and NTCP increased by stickwater with 16.9%, 68.2% and 222.8%, respectively, in SW25 group. The mRNA level of ABCC4 and NTCP varied significantly (P<0.05). The results indicated that addition of 25% stickwater (dry matter) in diets without fish meal had no effect in liver bile acid synthesis, but it promoted transferring bile acid to serum and intestine to improve fat metabolism and reduce fat deposition in yellow catfish.