Effects Of Dietary Fat And Phospholipids On Growth, Liver Antioxidant Capacity And Serum Biochemical Index Of Hybrid Channa

Lipids are important source of energy metabolism and cell renewal for fish. Diets with proper lipids can improve the fish growth performance and feed efficiency, and have a protein sparing effect. However, improper addition will lead to excessive lipid deposition and impaire fish health. Dietary phospholipids have beneficial effects on lipid digestion and transport, and reduce larval deformities. Hybrid snakehead is one of the important economic fish in China. At present, scarce information is available about the nutritional research on hybrid snakehead, which surly imposes restrictions on the development of its aquaculture industry. Therefore, our study, with hybrid snakehead(Channa argus ×Channa maculata) as the object, explored the effect of dietary lipid and phospholipid levels on growth, liver antioxidant ability and serum biochemical indexes of fish, in order to provide references and theoretical foundation for the aquatic feed formulation. 1、 Effects of dietary lipid levels on growth, liver antioxidant ability and serum biochemical indexes of hybrid snakeheadThe study was conducted to evaluate the effect of dietary lipid levels on growth, liver antioxidant ability and serum biochemical indexes of hybrid snakehead(Channa argus × Channa maculata). Five isonitrogenous(crude protein 420 g kg-1) practical diets containing 58, 87, 115, 144 and 173 g kg-1 crude lipid were fed to triplicate groups of 30 fish(mean initial weight 24.14±0.59 g) for 8 weeks. The results showed that the final body weight, specific growth rate and protein efficiency ratio increased significantly with the increasing dietary lipid levels(P<0.05). Liver lipid contents and crude lipid of whole body increased with increasing dietary lipid levels and reached the highest values in fish of L173(P<0.05). Moisture and crude protein of whole fish showed decreasing trend(P<0.05). Fish fed diet with 173 g kg-1 lipid showed lower alkaline phosphatase and catalase activities but higher malondialdehyde content in liver than the other groups(P<0.05). Higher alanine transaminase activity, aspartate transaminase activity and triglyceride in serum were observed in fish fed diet with 17.3 g kg-1 lipid compared to the other treatments(P<0.05). Fish fed diet with 144 g kg-1 lipid showed higher superoxide dismutase activity and glutathione peroxidase activities in liver than that of fish fed diet L58(P<0.05). Fish fed diet with 58 g kg-1 lipid showed lower total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol in serum(P<0.05). These results suggested that dietary lipid could significantly improve the growth performance of hybrid snakehead(Channa argus × Channa maculata). Diet with 143 g kg-1 lipid was more conductive to liver health. The appropriate dietary lipid supplementation needs to be determined in further studies. 2、 Effects of dietary lipid levels on growth, liver antioxidant ability and serum biochemical indexes of hybrid snakeheadThe study was conducted to evaluate the effect of dietary phospholipid levels on growth, liver antioxidant ability and serum biochemical indexes of hybrid snakehead(Channa argus × Channa maculata). Five isoenergetic(gross energy 18.21 MJ Kg-1) and isonitrogenous(crude protein 430 g kg-1) practical diets were formulated to contain graded levels of phospholipid(9, 15, 21, 27 and 33 g kg-1) were fed to triplicate groups of 30 fish(mean initial weight 18.70±0.03 g) for 8 weeks. The results showed that no significant difference was observed in final body weight, specific growth rate and survival rate among all groups(P>0.05). Fish fed diet with 33 g kg-1 phospholipid showed higher feed conversion ratio and feed intake, but lower protein efficiency ratio than the other groups(P<0.05). Intraperitoneal fat ratio, viscera ratio and hepatosomatic index showed no difference among all groups(P>0.05). Fish fed diet with 21 g kg-1 phospholipid showed higher catalase and superoxide dismutase activities, but lower malondialdehyde content(P<0.05) in liver. The dietary phospholipid levels showed no significant effect on glutathione peroxidase activity in liver among all groups(P>0.05). No significant differences were found in total cholesterol, triglyceride, high density lipoprotein cholesterol and low density lipoprotein cholesterol among all groups(P>0.05). In conclusion, dietary phospholipid supplementation have no beneficial effect on the growth performance of hybrid snakehead(Channa argus × Channa maculata). Diet with 21 g kg-1 phospholipid has more advantage effect on the liver health of hybrid snakehead.