Influence of supplementation of all-rac-[alpha]-tocopheryl acetate preweaning and vitamin C postweaning on [alpha]-tocopherol and immune responses of piglets

This study was designed to test whether dietary maternal supplementation of all-rac-[alpha]-tocopheryl acetate during lactation and dietary vitamin C supplementation after weaning could increase the [alpha]-tocopherol status pre- and postweaning and the immune responses of piglets postweaning. The experiment involved 12 crossbred sows that were fed increasing levels of all-rac-[alpha]-tocopheryl (70, 150, and 250 IU/ kg, as-fed basis) during lactation. After weaning (d 28 of age), litters were divided into two groups that were supplemented with or without vitamin C (500 mg/kg of feed, as-fed basis). Milk and blood samples were obtained from the sows during lactation. Pigs were bled at 4, 16, 28, 35, 42, and 49 d of age. Liver, heart, muscle, and s.c. adipose tissues were collected (on 28, 35, 42, and 49 d of age) and analyzed for [alpha]-tocopherol. On the same days, alveolar macrophages of the lungs were collected, and analyzed for the concentration of [alpha]-tocopherol and its stereoisomer composition, fatty acid composition, and release of prostaglandin [E.sub.2], leukotriene [B.sub.4], and thromboxane [B.sub.2]. Increasing dietary all-rac-[alpha]-tocopheryl acetate concentration increased the concentration of [alpha]-tocopherol in plasma (P = 0.02) and milk (P = 0.007) of sows, and the sow milk concentrations of [alpha]-tocopherol and vitamin A were greater on d 2 of lactation than later on during lactation. The plasma concentration of [alpha]-tocopherol in piglets decreased from d 4 to later on during suckling (P < 0.001) and again as the postweaning period progressed (P < 0.001). When lipid-standardized, plasma [alpha]-tocopherol was increased in piglets of sows fed 250 IU of all-rac-[alpha]-tocopheryl acetate compared with other sow-groups (P = 0.005). At 28 d of age, [alpha]-tocopherol concentrations in tissues were increased with supplementation of the high dietary all-rac-[alpha]-tocopheryl acetate levels to the sows; however, after weaning, a decrease in [alpha]-tocopherol concentration in most tissues (except liver) was observed, but the decrease tended to be less in the muscle (P = 0.099) and adipose tissue (P = 0.11) of piglets suckling sows fed 150 and 250 IU of all-rac-[alpha]-tocopheryl acetate. Vitamin C supplementation after weaning increased liver [alpha]-tocopherol (P = 0.01) and serum immunoglobulin M concentration (P = 0.04), and vitamin C supplementation increased the proportion of the RRR-[alpha]-tocopherol (P = 0.03) at the expense of the RRS-stereoisomer form (P = 0.05) of [alpha]-tocopherol in alveolar macrophages of the piglets. In conclusion, this study on maternal all-rac-[alpha]-tocopheryl acetate and postweaning vitamin C supplementation suggests a nutritional strategy for increasing [alpha]-tocopherol status and immune responses of weaned piglets. Key Words: Immune Response, Pigs, Tocopherol, Vitamin E, Vitamin C, Weaning