Dietary soybean phospholipids increase the oxidative stability of lipids extracted from fish fillets

We previously reported that the feeding of soybean phospholipids to fish increased the storage stability of n-3 polyunsaturated fatty acids (PUFA)-rich fish fillets. In this study, we examined the storage stability of lipids extracted from fish fed a diet containing soybean phospholipids and fish oil. Rainbow trout were divided into two groups, and were fed an either 2.5% soybean phospholipids (test) or no phospholipids (control) containing diet for 4 weeks. Lipids were extracted from fish fillets after the feeding period, and were subjected to an oxidation test. Lipids extracted from the fillets of fish in the test group exhibited lower values of oxygen absorption than those in the control group, and the degradation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) was inhibited. Higher percentages of DHA and EPA were bound to phosphatidylcholine and phosphatidylethanolamine in the extracted lipids in the test group than in the control group. These results indicate that the oxidative stability of lipids extracted from fish fed soybean phospholipids is high, and that the higher percentages of DHA and EPA in PC and PE may have resulted in the higher stability of the lipids extracted from fish fillet.