Supplementation of Vitamin C to Weaner Diets Increases IgM Concentration and Improves the Biological Activity of Vitamin E in Alveolar Macrophages

Abstract

Vitamins E and C have been found to increase the cellular and humeral immunity of pigs. Vitamin E deficiency has also been found to predispose pigs to different diseases, E. coli infection is one among them. After weaning, the vitamin E status of pigs often decreases to a critical low level. In this experiment, we studied whether vitamin C supplementation would be a possible feeding strategy to optimize the immune status of weaners. The interaction between vitamin E and C is interesting due to the reported sparing action on vitamin E or synergism between these to vitamins. Piglets were weaned at day 28 of age from sows fed increasing dietary vitamin E during lactation, and piglets were during the following 3 weeks fed either a control diet or this diet supplemented with 500 mg STAY‐C per kg. Blood sampling was obtained weekly from day 28 and until day 49 of age. On the same days, one piglet per dietary treatment was killed and alveolar macrophages (AM) were harvested. Vitamin C supplementation increased the concentration of IgM in serum of piglets throughout the weaning period. Although the vitamin E concentration in AM decreased with increasing age of the piglets, the concentration was numerically higher in piglets of sows fed the high dietary level of vitamin E. However, vitamin C supplementation tended to increase the total AM concentration of vitamin E after weaning and increased the proportion of the biologically most active isomer of vitamin E [RRR‐(α‐tocopherol)] in the AM. The eicosanoid synthesis by AM was not influenced by the vitamin C supplementation, but the synthesis of leukotriene B4 was decreased 2 weeks after weaning compared to other days of AM harvesting. In conclusion, dietary vitamin C supplementation improved the immune responses of piglets after weaning.