Replacement of fish oil with vegetable oil blends in feeds for greater amberjack (Seriola dumerili) juveniles: Effect on growth performance, feed efficiency, tissue fatty acid composition and flesh nutritional value

Abstract

This study was undertaken to assess the effects of fish oil (FO) substitution by a mixture of alternative vegetable oils (VO) on Seriola dumerili culture performance. A 154- day feeding experiment was conducted using juveniles (39.2 ± 1.6 g average weight). Three isolipidic and isoenergetic meal-based diets were formulated varying their lipid component. The control diet contained 100% FO (FO100), whereas diets VO50 and VO100 included 1/2 of oil blend and all the oil from blend of palm oil (PO) and linseed oil (LO) as substitute for FO, respectively. Dietary regime did not significantly affect growth performance, biometric indices, feed efficiency, plasma chemistry and liver and muscle lipid contents. Nonetheless, dietary VO inclusion impacted on the fatty acid profile of target tissues, especially in the liver. Fatty acid profiles of the fillets reflected those of the dietary oils except that there was apparent selective utilization of palmitic acid (C16:0) and oleic acid (C18:1n-9) and apparent selective retention of long-chain polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3). The nutritional value and the potential ability to prevent the development of coronary heart diseases of the flesh lipid fraction decreased with gradual FO substitution.