Effect of injected vitamin A and level of dietary vitamin E on alpha-tocopherol status in gestating swine

A 2 x 2 trial was conducted to determine the effects of injected vitamin A and dietary level of vitamin E on blood serum and tissue concentrations of alpha-tocopherol during early gestation of gilts. Thirty-two crossbred gilts were fed a corn soybean meal basal diet supplemented with DL-alpha tocopheryl acetate to provide either 25 or 500 IU of vitamin E/kg of diet. Gilts were fed daily 1.9 kg/gilt beginning 7 days before breeding until day 25 of gestation. Sixteen gilts were injected (i.m.) with 350,000 IU of retinol palmitate 7 days before breeding, at the time of breeding (d0), and 7 days after breeding. Blood samples were collected on day -7, 0, 7, and 24, and all gilts were slaughtered on day 25 of gestation. Supplemental vitamin E at 500 IU/kg of diet increased alpha-tocopherol concentrations (P < 0.01) in blood serum in all tissues examined, including reproductive and embryonic, except fat. Vitamin A injections had no effect (P > 0.10) on blood serum alpha-tocopherol concentrations except on day 7 when a small increase (P < 0.06) was noted. Vitamin A injections had no effect (P > 0.10) on tissue alpha-tocopherol concentrations. Increasing dietary level of vitamin E increased blood serum and tissue alpha-tocopherol concentrations, and vitamin A injections had little or no effect on these concentrations during the early gestation of gilts.