THE EFFECT OF DIETARY ALPHA-TOCOPHERYL ACETATE SUPPLEMENTATION ON MUSCLE ALPHA-TOCOPHEROL LEVELS AND LAMB QUALITY

The effects of dietary alpha-tocopheryl acetate supplementation on the uptake of alpha-tocopherol in lamb M. triceps brachii caput longum, M . biceps brachii, M. gluteus medius and M. semimembranosus and on the oxidative and colour stability of frozen M. semimembranosus were inves tigated. Pregnant ewes (n = 12) were divided into two groups (n = 6). The control group was fed a diet containing 20 mg alpha-tocopheryl ace tate / kg feed / day and the supplemented group fed a diet containing 1000 mg alpha-tocopheryl acetate / kg feed / day, for 9 weeks pre-part um and 3 weeks post-partum. Lambs were weaned at 3 weeks of age and fe d supplemented or basal feed for 10 weeks prior to slaughter. Suppleme ntation increased the alpha-tocopherol levels in all tissues sampled. Frozen storage, at -20 degrees C for 36 weeks, reduced the mean alpha- tocopherol levels in all muscles. Reduction was statistically signific ant (P < 0.05) only in M. semimembranosus. Supplementation significant ly (P < 0.05) inhibited induced lipid peroxidation in frozen (-20 degr ees C for 22 weeks) and thawed (4 degrees C x 12 h) M. semimembranosus . Surface discoloration of frozen M. semimembranosus during subsequent refrigerated display was not affected by supplementation. However, a significant (P < 0.05) decrease in the proportion of metmyoglobin was noted after 6 days of storage.