Effects of dietary 25-hydroxycholecalciferol supplementation on growth performance, blood vitamin D and antioxidant status in nursery pigs

Objective: This study was conducted to evaluate the effect of dietary 25-hydroxycholecalciferol (25-OHD₃) supplementation on growth performance, blood 25-OHD₃ level, and antioxidant parameters in nursery pigs.Methods: A total of 48 newly weaned piglets (5.27±1.42 kg initial body weight) were allotted to 3 treatments in 4 replicates with 4 pigs per pen for a 28-d feeding trial in two phases for d 0–14 (Phase 1) and d 14–28 (Phase 2) postweaning with basal diets without supplemental vitamin D₃ (VD₃). Treatments were: 1) basal diet+2,000 IU/kg VD₃ supplementation, 2) basal diet+1,000 IU/kg 25-OHD₃ supplementation, and 3) basal diet+2,000 IU/kg 25-OHD₃ supplementation. Growth performance, plasma 25-OHD₃ and malondialdehyde (MDA) levels, total antioxidant capacity, and superoxide dismutase activity were measured.Results: There was no significant difference in growth performance among dietary treatments until d 21 postweaning. Dietary 25-OHD₃ supplementation increased feed intake (p<0.07) and growth rate (p<0.05) greater than the VD₃ treatment in d 21–28 and d 14–28 postweaning, resulting in a greater growth rate in the overall period (p = 0.10). Increasing levels of 25-OHD₃ supplementation resulted in greater plasma 25-OHD₃ concentrations at d 14 and 28 postweaning (p<0.05), while decreasing plasma MDA levels at d 28 postweaning (p<0.05) with no differences in plasma superoxide dismutase activity and total antioxidant capacity. In the broken-line analysis, the estimated plasma 25-OHD₃ concentration for plasma MDA concentration to reach the minimum level was 23.7 ng/mL (p<0.05).Conclusion: Supplementing 25-OHD₃ in nursery diets increased blood vitamin D status and had potential to enhance feed intake and growth rate in the late nursery period, while reducing oxidative stress compared with VD₃ supplementation.