The Effects of Diets Containing Standard Soybean Oil, Soybean Oil Enhanced with Conjugated Linoleic Acids, Menhaden Fish Oil, or an Algal Docosahexaenoic Acid Supplement on Channel Catfish Performance, Body Composition, Sensory Evaluation, and Storage Characteristics

Abstract Fish consumption is a common method of obtaining beneficial n-3 highly unsaturated fatty acids (LC-PUFAs), but increased use of vegetable oils in fish diets to reduce dependence on fish oil dilutes the amounts of LC-PUFAs. Conjugated linoleic acids (CLAs) are also considered beneficial for human health. Therefore, we investigated four different lipid sources in Channel Catfish Ictalurus punctatus diets for their ability to enhance fatty acid profiles of fillets to benefit human health while maintaining or improving fish performance. In a 175-d grow-out trial, Channel Catfish (71.4 ± 0.1 g [mean ± SE]) were fed a commercial 32% protein diet supplemented with 2% lipid from soybean oil (SO), soybean oil enhanced with conjugated linoleic acids, menhaden fish oil (FO), or an algal supplement of Schizochytrium sp. high in 22:6(n-3) (docosahexaenoic acid, DHA). Diet effects were assessed by measuring fish growth performance, muscle proximate and fatty acid composition, sensory characteristics of fillets, consumer taste preferences, and oxidative stability of fillets during cold storage. There were no differences in fish growth performance or proximate composition. Only fish fed the CLA diet contained CLAs in the muscle. Fish fed the FO and algal DHA diets had higher concentrations of 22:6(n-3) in the muscle compared with fish fed the SO and CLA diets. Sensory evaluation and consumer preference testing were more favorable for fillets from fish fed the SO and CLA diets than from fish fed the FO and algal DHA diets. There were no differences in storage characteristics of fish refrigerated at 4°C for 2 weeks or frozen at −18°C for 4 weeks. Fillets from fish fed the FO diet yielded the highest concentration of fatty acids for human health benefits, followed by the fillets from fish fed the algal DHA diets. The CLA diet produced increased fillet concentrations of CLAs.