The Effects of Fat-soluble Vitamin Administration on Plasma Vitamin Status of Nursing Pigs Differ When Provided by Oral Administration or Injection

Four experiments were conducted to investigate the effect of fat-soluble vitamin administration to sows or newborn pigs on plasma vitamin status. In Exp. 1 and 2, a total of 24 and 43 newborn pigs were allotted to control and vitamin treatments (vitamin $D_3$ with variable addition of vitamins A and E) orally or by i.m. injection. In Exp. 3, pigs from Exp. 2 were allotted to 2 treatments (${\alpha}$vitamins $D_3$ and E in drinking water) for 14 d postweaning. In Exp. 4, twenty-four gestating sows were used for 2 treatments (${\pm}injection$ of a vitamin $D_3$/A/E product 2 wk prepartum). In Exp. 1 and 2, when vitamin $D_3$ was administrated orally or by i.m. injection on d 1 of age, pigs had increased plasma 25-hydroxycholecalciferol (25-OH $D_3$) concentration 10 d after administration compared with control pigs (p<0.05). The injectable administration with vitamin $D_3$ and E was able to achieve higher plasma 25-OH $D_3$ (p<0.05) and ${\alpha}$-tocopherol (p<0.05) concentrations than oral administration. At weaning, the pigs in the injection group had higher plasma 25-OH $D_3$ concentration than those in the other groups in both studies (p<0.05). In Exp. 3, water supplementation of vitamin $D_3$ and E postweaning increased plasma 25-OH $D_3$ and ${\alpha}$-tocopherol concentrations at d 14 postweaning (p<0.01). In Exp. 4, when sows were injected with the vitamin $D_3$ product prepartum, serum 25-OH $D_3$ concentrations of sows at farrowing (p<0.01), and in their progeny at birth (p<0.01) and weaning (p<0.05) were increased. These results demonstrated that fat-soluble vitamin administration to newborn pigs increased plasma 25-OH $D_3$ concentration regardless of administration routes and ${\alpha}$-tocopherol concentration by the injectable route, and that water supplementation of vitamin $D_3$ and E to nursery pigs increased plasma 25-OH $D_3$ and ${\alpha}$-tocopherol concentrations. Additionally, injecting sows with vitamin $D_3$ prepartum increased 25-OH $D_3$ in sows and their offspring. If continued research demonstrates that the serum levels of 25-OH $D_3$ are critical in weanling pigs, a variety of means to increase those levels are available to swine producers.