Effects of different lipid sources on growth performance, body composition, the serum biochemical indices, fatty acids composition and antioxidant capacity in juvenile yellow catfish (Pelteobagrus fulvidraco)

An 8-week feeding trial was conducted to evaluate the effects of different lipid sources on growth performance, body composition, the serum biochemical indices, fatty acids composition and antioxidant capacity in juvenile yellow catfish. Four isoproteic and isolipidic diets were formulated to contain different lipid sources: coconut oil, perilla oil, sunflower oil, fish oil+sunflower oil (1∶1) mix oil, respectively, on the basis of adding soybean oil. Each diet was randomly assigned to feed three replicate groups of juvenile yellow catfish whose initial body weight was approximately (1.52±0.00) g. The results showed that the different dietary lipid sources didn’t have significant influence on final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and survival rate (SR), but had significant differences in feed conversion ratio (FCR). The SR of all groups was more than 95%. The hepatosomatic index (HSI) and condition factor (CF) showed significant differences among all groups. However, they didn’t have significant differences in the viscerosomatic index (VSI) and intraperitoneal fat ratio (IPR). The HSI and CF of fish fed fish oil+sunflower oil (1∶1) mix oil were significantly higher than other groups. The moisture, the crude protein, the ash content were not significantly affected by lipid sources. But the crude lipid of fish fed coconut oil, which was 10.51%, was significantly higher than other groups. Fatty acid composition of muscle and liver in fish generally reflected the composition of the diet. Furthermore, the different dietary lipid sources had significant differences in the fatty acid composition in the muscle and liver. The saturated fatty acid (SFA) content of fish fed coconut oil was the highest, the α-linolenic acid (ALA) and n-3 polyunsaturated fatty acids (n-3 PUFA) content of fish fed perilla oil the were the highest, the linoleic acid (LA) and n-6 polyunsaturated fatty acids (n-6 PUFA) content of fish fed sunflower oil were the highest, and the fatty acid composition of fish fed fish oil+sunflower oil (1∶1) mix oil is more balanced. No significant difference was found among all treatments in total protein (TP), albumin (ALB), globulin (GLOB), A/G, aspartate aminotransferase (AST), total cholesterol (CHOL), triglyceride (TG), blood glucose (GLU) and creatine kinase (CK) in the serum. While the activities of sulyperoxide dismutase (SOD), malondialdehyde (MDA) and glutathione S-transferase (GST) in liver were significantly influenced by lipid sources. Fish fed coconut oil had significantly higher activity of SOD as well as GST, but lower content of MDA, in serum than the other treatments. These results indicate that coconut oil, perilla oil, sunflower oil and fish oil+sunflower oil (1∶1) mix oil can be used as dietary lipid sources of yellow catfish, on the basis of adding soybean oil. And the fatty acid composition of fish body basically reflected the fatty acid composition of diet and the essential fatty acids of freshwater fish were LA and ALA.