Dietary supplementation versus direct postmortem addition of α-tocopherol acetate on fatty acid composition of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage

This study was designed to compare the effects of α-tocopherol acetate which added to diet (0, 300 and 500 mg/kg) in 58 days trial and direct addition (200 mg/kg flesh) after slaughtering on fatty acid composition of rainbow trout fillets during 12 days of refrigerated storage. Fish were fed experimental diets twice daily at 8:00 and 17:00 h, 7 days a week. The present study illustrated that dietary α-tocopherol acetate showed no statistically difference (P 0.05) in fillet composition parameters and content of the major fatty acid groups of fish fillets after 8 weeks experiment. In general, there was decrease in the proportion of MUFA and PUFA, and an increase of SFA in all treatments during refrigerated storage (P 0.05). However, during storage period, the fatty acid composition was not affected by the postmortem addition of vitamin E, but fish that fed supplemented diets with α-tocopherol acetate had less change in fatty acids in comparison to the control diets at the end of refrigerated storage (P 0.05). There were no significant differences in FA composition (P 0.05) between the fillets of fish fed diets containing different levels of α-tocopherol during storage period.