Influence of dietary fat and vitamin E supplementation on alpha-tocopherol levels and fatty acid profiles in chicken muscle membranal fractions and on susceptibility to lipid peroxidation

Broiler chickens were fed a basal feed supplemented with 10% tallow or. olive oil and varying levels of vitamin E (20 and 200 mg vitamin E/kg feed). The concentration of alpha-tocopherol in the membranes of breast and thigh muscles was significantly influenced by the alpha-tocopherol level in the feed (p < 0.001). Deposition of vitamin E was not influenced by the type of oil in the feed, except in the mitochondrial fraction of breast where the vitamin E concentration was higher in those fed olive oil than in those fed tallow (p < 0.05). Dietary oil influenced the fatty acid composition of the muscle membranal fractions (p < 0.001). The oxidative stability of the membranal fr actions tended to increase with increasing concentrations of alpha-tocopherol in the membranal fractions. In conclusion, the supplementation of vitamin E appeared to enhance the stability of muscle to oxidation. Thus, incorporation of alpha-tocopherol into the membranes via dietary manipulation helped in stabilizing the membrane-bound lipids. (C) 1997 Elsevier Science Ltd.