Impact of dietary peroxides and tocopherols on fillet flavor of farmed Atlantic salmon

The Atlantic salmon (Salmo salar) is a suitable model for animal research on the impact of oxidation of feedstuff oils and fish meal lipids on product quality. This species not only has an absolute requirement for dietary long-chain n-3 polyunsaturated fatty acids (20:5n-3, 22:6n-3) for the subcellular membrane lipids, but also deposits these same fatty acids in the muscle depot fats. Peroxides may retard growth and potentially affect fillet flavor. Traditionally only alpha-tocopherol has been boosted in salmon diets, but we have now shown that gamma-tocopherol may also be deposited in salmon muscle total lipids. It appears that if both tocopherols are fed, alpha-tocopherol will be found in phospholipid-rich organ tissues and gamma-tocopherol in the adipocytes which known to be the principal sites for triacylglycerol storage in the muscle. Our initial studies suggest that in any long-term post-slaughter storage of salmon gamma-tocopherol could be an asset in preventing rancidity.