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 D₃ 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 (±vitamins D₃ and E in drinking water) for 14 d postweaning. In Exp. 4, twenty-four gestating sows were used for 2 treatments (±injection of a vitamin D₃/A/E product 2 wk prepartum). In Exp. 1 and 2, when vitamin D₃ was administrated orally or by i.m. injection on d 1 of age, pigs had increased plasma 25-hydroxycholecalciferol (25-OH D₃) 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 D₃ (p<0.05) and a-tocopherol (p<0.05) concentrations than oral administration. At weaning, the pigs in the injection group had higher plasma 25-OH D₃ concentration than those in the other groups in both studies (p<0.05). In Exp. 3, water supplementation of vitamin D₃ and E postweaning increased plasma 25-OH D₃ and a-tocopherol concentrations at d 14 postweaning (p<0.01). In Exp. 4, when sows were injected with the vitamin D₃ product prepartum, serum 25-OH D₃ 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 D₃ concentration regardless of administration routes and α-tocopherol concentration by the injectable route, and that water supplementation of vitamin D₃ and E to nursery pigs increased plasma 25-OH D₃ and α-tocopherol concentrations. Additionally, injecting sows with vitamin D₃ prepartum increased 25-OH D ₃ in sows and their offspring. If continued research demonstrates that the serum levels of 25-OH D₃are critical in weanling pigs, a variety of means to increase those levels are available to swine producers.