Effects of dietary supplementation with vitamin E and organic selenium on the oxidative stability of beef

The effects of supplementation of beef cattle diets with organic Se (0.3 mg /kg) and vitamin E (300 I.U. alpha -tocopheryl acetate/kg feed), for 55 d p receding slaughter, on the antioxidant status and oxidative stability of mu scle was examined. Dietary vitamin E supplementation led to an increase (P < 0.05) in plasma, and longissimus muscle alpha -tocopherol levels. In minc ed longissimus muscle stored in 80% O-2:20% CO2, lipid and oxymyoglobin oxi dation were lower (P < 0.05) in muscle from vitamin E-supplemented animals compared with unsupplemented animals. Dietary Se supplementation did not si gnificantly affect muscle Se levels, glutathione peroxidase activity, or su sceptibility to lipid and oxymyoglobin oxidation in the presence or absence of vitamin E. Covariance analysis indicated that, in addition to muscle al pha -tocopherol, differences in muscle glutathione peroxidase activity, and pH could account for variation in the susceptibility of muscle to lipid an d oxmyoglobin oxidation.