Effects of 25-hydroxycholecalciferol supplementation in late gestation and lactation diets on reproductive and litter performance, vitamin D status, milk composition, antioxidant capacity, and immune response in sows and their progeny

This study was conducted to evaluate the effect of 25-hydroxycholecalciferol (25-OHD3) supplementation replacing vitamin D3 (VD3) in late gestation and lactation diets on reproductive and litter performance, milk composition, immunoglobulin concentrations, and antioxidant capacity in sows and their progeny. A total of 30 sows in late gestation (d 105-108 of gestation) were allotted to 3 treatments in 10 replicates and fed experimental lactation diets until weaning. Treatments were: 1) VD: basal diet with 2,000 IU/kg VD3 supplementation; 2) MIX: basal diet with 1,000 IU/kg VD3 + 1,000 IU/kg 25-OHD3 supplementation; and 3) 25D: basal diet with 2,000 IU/kg 25-OHD3 supplementation. Blood, colostrum, and milk samples were collected at farrowing and d 14 of lactation, and data were analyzed using PROC MIXED of SAS. No significant differences were observed in reproductive and litter performance among dietary treatments. Sows fed MIX and 25D had greater sow plasma 25-OHD3 levels compared to sows fed VD at farrowing and d 14 of lactation (P < 0.05), while sows fed the 25D had greater plasma 25-OHD3 levels than sows fed MIX at d 14 of lactation. Piglets from the 25D sows tended to have greater plasma 25-OHD3 levels than those from VD sows at birth (P = 0.07) with piglets from MIX sows having intermediate values. Sows fed 25D had greater colostrum fat content than those fed VD (P < 0.05). Sows fed the 25D had greater superoxide dismutase activity in plasma at farrowing (P < 0.05) and in colostrum (P = 0.06) than those fed VD and MIX. Sows fed MIX or 25D had greater plasma total antioxidant capacity (T-AOC) at farrowing (P < 0.05) than those fed the VD while sows fed the 25D had greater plasma T-AOC than those fed VD or MIX at d 14 of lactation (P < 0.05). Piglets from the MIX sows tended to have lower plasma malondialdehyde (P = 0.09) and greater plasma T-AOC (P = 0.06) at birth than those from VD sows, whereas no differences were observed in plasma superoxide dismutase activity. Sows fed MIX had greater colostrum immunoglobulin G concentrations than those fed VD (P < 0.05), although there was no difference in plasma immunoglobulin G concentrations in piglets. In conclusion, dietary 25-OHD3 supplementation partially or fully replacing VD3 in sow diets from late gestation through lactation improved vitamin D status, colostrum fat contents, immunoglobulin G concentrations, and sow and piglet antioxidant capacity without affecting reproductive or litter performance.