The effect of dietary α-tocopheryl acetate supplementation on muscle α-tocopherol levels and lamb quality

The effects of dietary α-tocopheryl acetate supplementation on the uptake of α-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 investigated. Pregnant ewes (n = 12) were divided into two groups (n = 6). The control group was fed a diet containing 20 mg α-tocopheryl acetate/kg feed/day and the supplemented group fed a diet containing 1000 mg α-tocopheryl acetate/kg feed/day, for 9 weeks pre-partum and 3 weeks post-partum. Lambs were weaned at 3 weeks of age and fed supplemented or basal feed for 10 weeks prior to slaughter. Supplementation increased the α-tocopherol levels in all tissues sampled. Frozen storage, at -20 °C for 36 weeks, reduced the mean α-tocopherol levels in all muscles. Reduction was statistically significant (P < 0.05) only in M. semimembranosus. Supplementation significantly (P < 0.05) inhibited induced lipid peroxidation in frozen (-20 °C for 22 weeks) and thawed (4 °C × 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.