Oxidative status of plasma and muscle in rabbits supplemented with dietary vitamin E

Thirty New Zealand white rabbits, mean weight 2 kg, were divided into three equal groups balanced for body weight and randomly assigned to a diet containing 60 (C), 150 (T1) or 375 (T2) mg/kg of all-rac-alpha-tocopheryl acetate. After 29 days, the animals were slaughtered. alpha-Tocopherol was assayed in muscle (longissimus dorsi) and plasma; triglycerides and cholesterol (total, high density lipoprotein, low density lipoprotein) were analysed in plasma; reactive oxygen metabolites (ROMs) were analysed in serum; and thiobarbituric acid-reactive substances (TBARS) were analysed in muscle. There were no body weight and food intake differences between the groups. The plasma vitamin E and vitamin E:lipid ratio were significantly higher in groups T1 and T2 than in C, but increases were not linearly related to dietary levels. Muscle alpha-tocopherol concentrations in the treated groups were significantly higher than in C, and linearly related (R =.67) to the vitamin E:lipid ratio. ROM and vitamin E levels in blood were inversely related (R =.74), with ROMs significantly lower in the treated groups than in C. The 60-mg/kg dose of C recommended by the National Research Council was unable to control ROM production. Lipid oxidation in muscle was significantly lower in T2 than in the other groups, and TBARS correlated significantly with muscle vitamin E (R =.61) and serum ROM (R =.73). These data suggest that vitamin E supplemented at 375 mg/kg diet can effectively control ROM production and improve muscle lipostability. ROM assay provides a useful indirect estimate of the oxidative status of muscle in vivo.