Enrichment of channel catfish (Ictalurus punctatus) fillets with conjugated linoleic acid and omega-3 fatty acids by dietary manipulation

An experiment was conducted in aquaria with channel catfish (Ictalurus punctatus) to determine the efficacy of augmenting fillets with conjugated linoleic acid (CLA) and omega-3 highly unsaturated fatty acids (n−3 HUFA) by feeding diets amended with products containing high levels of these nutrients. Refined menhaden fish oil at 1.5% of diet supplied the n−3 HUFA. CLAwas used at dietary levels of 0.5% and 1% with a preparation that contained approximately 65% isomers of CLA. Corn oil was added to the basal diet at maximum inclusion level for added lipids of 3% for the control diet and to adjust total added lipid content of the other diets to 3%. Average initial bodyweightwas 57.39±0.25 g/fish. Six experimental dietswere fed twice daily to four replicate aquaria for sixweeks.At that time, fish were group weighed for determination of weight gain and feed conversion. Fillets of six fish per aquariumwere recovered and stored at −80 °C for moisture and total lipid analyses, fatty acid analysis, and sensory evaluation. Results showed feed consumption and feed conversion did not differ (PN0.05). Significantly (Pb0.05) greater body weight gains were observed only for fish fed the diets with two combinations of CLA and 1.5% fish oil compared to fish fed the diet containing 0.5% CLA and corn oil. Fillet n−3 HUFA levels were significantly (Pb0.05) elevated for fish fed diets containing fish oil when compared to n−3 HUFA of fillets of fish fed diets containing either corn oil or CLA and corn oil. Similarly, fillets from fish fed diets amended with CLA contained substantial amounts of CLA of up to 6.4% of total lipids. Fillets from fish fed corn oil or fish oil diets had no CLA. Taste panel evaluation indicated that fillets containing n−3 HUFA andCLAwere essentially without fishy off-flavor and had excellent sensory qualities. Catfish fillets produced by amending diets with sources of n−3 HUFA andCLA at the levels used in this studywould contain elevated levels of these nutraceuticals and could be an important human food source for these healthful fatty acids. © 2006 Elsevier B.V. All rights reserved.