Three experiments, two with pigs and one with Atlantic salmon, (<I>Salmo salar</I>) were carried out to investigate the effects of dietary supplementation with α-tocopheryl acetate (ATA) on quality of pig and salmon tissues. In Experiment 1, 32 pigs were individually fed either of two dietary fat sources: 0.5:0.5 <I>w/w</I> coconut oil/lard (59 g/kg finisher diet) or rapeseed oil (100 g/kg finisher diet) (as contained in full-fat rapeseed {FFR}), with or without supplementary ATA at 200 mg/kg diet. In Experiment 2, 24 pigs were individually fed either a diet which contained mixtures of vegetable oil (59 g/kg diet) (having a high level of palm oil) or rapeseed oil diet as in Experiment 1. The rapeseed oil diets were supplemented with 0, 200 and 500 mg ATA/kg diet. In Experiment 3, a commercial diet with high lipid content (290 g/kg diet) and 250 mg ATA/kg diet was supplemented with 0, 400 and 700 mg ATA/kg diet. Diets were fed to 54 salmon. Tissue samples were stored at 4°C and/or -20°C for different periods. Spectral data on tissue samples were collected with an NIRSystems 6500 scanning monochromator. Salmon and pig tissues, and pig muscle subcellular fractions (microsomal and mitochondrial) were analysed for fatty acid composition, α-tocopherol (AT) content and oxidative stability (by thiobarbituric acid test). In both pigs and salmon, muscle drip loss was measured, and the colour score and carotenoid content of salmon fillets were determined. Data presented in this study indicate that pig tissues respond positively to increased dietary supply of unsaturated fatty acids (UFA). Pig tissue UFA and n-3 fatty acid contents were increased, and n-6/n-3 fatty acid ratio was decreased by feeding diets containing FFR. There was only a slight influence of dietary fatty acids on fatty acid composition of the subcellular membranes. AT concentration was higher in the mitochondrial fraction than the microsomal fraction. The mitochondrial fraction lipids had a higher content of UFA than those of the mcirosomal fraction. Supplemental dietary ATA increased the AT content of both pig and salmon tissues.