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/k g feed). The concentration of alpha-tocopherol in the membranes of bre ast and thigh muscles was significantly influenced by the alpha-tocoph erol level in the feed (p < 0.001). Deposition of vitamin E was not in fluenced by the type of oil in the feed, except in the mitochondrial f raction of breast where the vitamin E concentration was higher in thos e fed olive oil than in those fed tallow (p < 0.05). Dietary oil influ enced the fatty acid composition of the muscle membranal fractions (p < 0.001). The oxidative stability of the membranal fr actions tended t o increase with increasing concentrations of alpha-tocopherol in the m embranal fractions. In conclusion, the supplementation of vitamin E ap peared to enhance the stability of muscle to oxidation. Thus, incorpor ation of alpha-tocopherol into the membranes via dietary manipulation helped in stabilizing the membrane-bound lipids. (C) 1997 Elsevier Sci ence Ltd.