EFFECTS OF FOUR DIETARY LIPIDS ON THE PERFORMANCE OF GROWTH AND BODY COMPOSITION IN PACIFIC SALMON, ONCORHYNCHUY

An 8-week growth experiment was conducted to test four lipids on Pacific salmon,Oncorhynchuy. The fishes(initial body weight ca.110g) in triplicate groups were fed with 11.5 % of each lipid included into basic diet in cement ponds. The results showed that the survival rate(SR)of each group was similar,but the specific growth rate(SGR)of fish fed soybean lecithin diet were significantly higher than that of other three lipid groups(P<0.05), more than 27%,23% and 21% to fish fed fish oil diet, soybean oil diet and corn oil diet, respectively. The feed efficiency(FE)of fish fed soybean lecithin diet, soybean oil diet and corn oil diet were significantly higher than that of fish fed fish oil diet(P<0.05). The contents of lipid in liver and mesentery of fish fed corn oil,soybean lecithin diet and soybean oil diet were in different degree lower than those of fish fed fish oil diet,but the contents of lipid in muscle were relatively higher than those of fish fed fish oil diet. The ratios of total polyunsaturated fatty acids(ΣPUFA)in lipid of liver,muscle and mesentery of fish fed four lipid sources were slightly different,but the ratios of total n-3 polyunsaturated fatty acids(Σ3-PUFA)in lipid of liver,muscle and mesentery of fish fed corn oil, soybean lecithin diet and soybean oil diet were significantly lower than those of fish fed fish oil diet and the ratios of total n-6 polyunsaturated fatty acids(Σ6-PUFA)were significantly higher than those of fish fed fish oil diet(P< 0.05). The indices of plasma of lipolytase(Lipa),cholesterol(CHOL),triglyceride(TG) and high density lipoprotein(HDL-C) in fish fed corn oil, soybean lecithin diet and soybean oil diet were in different degree higher than those in fish fed fish oil diet. No pathological changes were found in fish fed all four different lipid diets throughout the examinations of anatomy and histology. The experimental results indicate that soybean lecithin is optimal dietary lipid in Pacific salmon feeding with soybean oil and breeding in freshwater. Corn oil and fish oil showed same effect on the performance of growth.All four lipid diet did not show negative effects on health and quality to Pacific salmon.