INFLUENCE OF DIETARY-FAT AND VITAMIN-E ON THE LIPIDS IN PORK MEAT

48 pigs (gilts and barrows) were divided into four groups and fed for three months on diets containing either 3% soya oil or 3% beef tallow, together with alpha-dl-tococopheryl acetate at either a basal (20 mg/kg feed) or a supplemented (200 mg/kg feed) level. The fatty acid compositions of the longissimus dorsi muscle (m.l.d.) and adipose (backfat) tissue were found to vary with dietary fats and sex. Gilts showed higher contents of polyene fatty acids (PFA) than barrows. The PFAs C20:4omega6, C22:4omega6, C22:5omega3 and C22:6omega3 were not affected by the diet. Levels of alpha-tocopherol in muscle and adipose tissue were 2.5 to 4.0 times higher in pigs on the supplemented diet compared to pigs on the basal diet. After storage at - 18-degrees-C for nine months the muscle tissues were subjected to iron-induced lipid peroxidation. Supplementation of the feed with alpha-tocopheryl acetate improved the oxidative stability of the muscle. The influences of dietary fat and sex on lipid peroxidation were reduced by supplemental alpha-tocopheryl acetate. Muscle tissue from the basal-diet/soya-oil group was more susceptible to lipid oxidation than muscle tissue from the basal-diet/beef-tallow group.