Plasma tocopherol in sheep and cattle after ingesting free or acetylated tocopherol

Two trials were carried out to evaluate the bioavailability of dl-α-tocopherol and dl-α-tocopherol acetate administered to sheep and cattle in a single oral dose. In the first trial, two groups of five sheep were used. They received 100 mg/kg body weight of either dl-α-tocopherol or its acetylated form. The blood plasma α-tocopherol tolerance curve area was higher in the dl-α-tocopherol group than in its ester form. The time to reach maximum plasma α-tocopherol concentration was less in the dl-α-tocopherol group than in its ester form. In a second trial, four heifers received the two forms (50 mg/kg body weight) in rotation after an appropriate washing period between the two dosings. Again, plasma tolerance curve area was greater in the cattle following administration of dl-α-tocopherol than its acetylated form.EEA Colonia BenitezFil: Hidiroglou, Nick N. University of Florida. Animal Science Department; Estados UnidosFil: McDowell, Lee Russell. University of Florida. Animal Science Department; Estados UnidosFil: Balbuena, Osvaldo. University of Florida. Animal Science Department; Estados Unidos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Colonia Benítez; Argentina

Sparing effects of selenium and ascorbic acid on vitamin C and E in guinea pig tissues

BACKGROUND: Selenium (Se), vitamin C and vitamin E function as antioxidants within the body. In this study, we investigated the effects of reduced dietary Se and L-ascorbic acid (AA) on vitamin C and α-tocopherol (AT) status in guinea pig tissues. METHODS: Male Hartley guinea pigs were orally dosed with a marginal amount of AA and fed a diet deficient (Se-D/MC), marginal (Se-M/MC) or normal (Se-N/MC) in Se. An additional diet group (Se-N/NC) was fed normal Se and dosed with a normal amount of AA. Guinea pigs were killed after 5 or 12 weeks on the experimental diets at 24 and 48 hours post AA dosing. RESULTS: Liver Se-dependent glutathione peroxidase activity was decreased (P < 0.05) in guinea pigs fed Se or AA restricted diets. Plasma total glutathione concentrations were unaffected (P > 0.05) by reduction in dietary Se or AA. All tissues examined showed a decrease (P < 0.05) in AA content in Se-N/MC compared to Se-N/NC guinea pigs. Kidney, testis, muscle and spleen showed a decreasing trend (P < 0.05) in AA content with decreasing Se in the diet. Dehydroascorbic acid concentrations were decreased (P < 0.05) in several tissues with reduction in dietary Se (heart and spleen) or AA (liver, heart, kidney, muscle and spleen). At week 12, combined dietary restriction of Se and AA decreased AT concentrations in most tissues. In addition, restriction of Se (liver, heart and spleen) and AA (liver, kidney and spleen) separately also reduced AT in tissues. CONCLUSION: Together, these data demonstrate sparing effects of Se and AA on vitamin C and AT in guinea pig tissues

Relative Bioavailability of RRR- and All-Rac-α-Tocopheryl Acetate in Humans: Studies Using Deuterated Compounds

Vitamin E in nutritional supplements in its most common form is α- tocopheryl acetate. Available stereoisomeric forms are RRR- (1 stereoisomer) and all-rac- (8 stereoisomers). We evaluated the relative bioavailability of RRR- and all-rac-α-tocopheryl acetate using the deuterium-labeled isotopes [5-CD3] 2R, 4\u27R and 8\u27R-α-tocopheryl acetate (d3), and [5,7-(CD3)2]-all- rac-α-tocopheryl acetate (d6). Six adults (three males, three females), aged 25-59 y, received 150 mg each of d3 and d6 for 11 consecutive days. Blood samples were collected on days -1, 0, 1-11, 13, 14, 20, 25, 30, 60, 74, 88, 102, 122, and 137. Plasma and red blood cell tocopherol were evaluated by using HPLC and gas chromatography/mass spectrometry to distinguish between d3 and d6 tocopherols. Cholesterol, triglycerides, and LDL and HDL cholesterol were measured. Relative bioavailability of d3 when compared with d6 was 2.0 ± 0.06 when area under the plasma time concentration curve (AUC d3/d6) by trapezoidal rule (P \u3c 0.05) was used. Correcting for lipid yielded the same finding. Unlabeled tocopherol (d0) decreased (P \u3c 0.05) with vitamin E administration. It was concluded that the ratio of bioavailability of RRR- all-rac-α-tocopheryl acetate is significantly greater than the currently accepted ratio of 1.36