Distribution of α-tocopherol in beef muscles following dietary α-tocopheryl acetate supplementation

The objective of this study was to determine the effect of dietary vitamin E supplementation on the distribution and concentration of α-tocopherol in beef muscles. Crossbred cattle (n=8) were selected and divided into two groups and fed diets containing 20 (basal) and 3000 mg (supplemented) α-tocopheryl acetate/head/day for 135 days prior to slaughter. Carcasses were split centrally and chilled at 4°C for 10 days. Muscles (n=16) were identified and removed from the left side of each animal and stored at −20°C until required. Mean α-tocopherol levels in muscles were significantly (P<0.05) higher in all supplemented muscles with the exception of m. infraspinatis and m. deltoidous compared to controls. Mean α-tocopherol levels in muscles from the supplemented group decreased in the order m. supraspinatis > m. psoas major > m. trapezius > m. gluteus medius > m. triceps caput brachii lumborum > m. rhomboidous > m. seratus ventralis > m. gluteobiceps > m. semitendinosus > m. semimembranosus > m. infraspinatis > m. subscapularis > m. tricepscaputbrachiilaterale > m. deltoidous > m. longissimus thorasis > m. longissimus lumborum. Significant (P<0.05) differences in α-tocopherol distribution within muscles were observed for supplemented m. psoas major and control m. seratus ventralis (highest levels in posterior ends and lowest in anterior ends) only. However, trends showed definite distribution patterns for other muscles. Levels of α-tocopherol were found to be highest in oxidative muscles (m. psoas major and m. gluteus medius) and lowest in glycolytic muscles (m. longissimus thoracis and m. longissimus lumborum) while moderate levels of α-tocopherol occurred in intermediate muscles (m. semimembranosus).