Dietary Supplementation of 25-Hydroxyvitamin D 3 Improves Growth Performance, Antioxidant Capacity and Immune Function in Weaned Piglets.

This study was conducted to evaluate the effects of 25-hydroxyvitamin D 3 (25(OH)VD 3 ) and Vitamin D 3 (VD 3 ) supplemented in the diet of weaned piglets on their growth performance, bone quality, intestinal integrity, immune function and antioxidant capacity. A total of 192 weaned piglets were allocated into four groups and they were fed a control diet containing 2000 IU VD 3 (negative control, NC), NC + 100 ppm colistin sulfate (positive control, PC), NC + 2000 IU VD 3 (VD 3 ) and NC + 2000 IU 25(OH)VD 3 (25(OH)VD 3 ) . The results showed that 25(OH)VD 3 improved the growth performance, bone quality and antioxidase activity of piglets compared with the other groups. Meanwhile, 25(OH)VD 3 up-regulated ileal mRNA expressions of tight junction proteins and host defense peptides. The VD 3 group had an increased intestinal sIgA content and mRNA expression of pBD-1 compared with the NC group. Both groups of VD 3 and 25(OH)VD 3 altered the microbial β-diversity compared with the NC group, and 25(OH)VD 3 increased ileal concentrations of acetate and butyrate. In conclusion, our findings indicated that a regular dosage of 2000 IU VD 3 in the weaned piglets' diet did not achieve optimal antioxidant capacity and immune function. 25(OH)VD 3 had better growth performance than VD 3 at the same inclusion level, which is associated with the improved intestinal integrity and antioxidant capacity.