Effects of 25-hydroxycholecalciferol supplementation during gestation on sow performance, offspring development, and intestinal microbiota in sows and piglets.

The 25-hydroxycholecalciferol (25OHD3) is a metabolite of vitamin D (VD) and status biomarker of VD in blood. We investigate the effect of dietary 25OHD3 supplementation on gestation sow litter performance, milk composition, nutrient metabolism, the growth performance of offspring, and intestinal microbiota. A total of 60 sows were randomly allocated to receive VD3 diet (CON, 50 µg·kg-1, n = 30) or 25OHD3 diet (50 µg·kg-1, n = 30). All sows had the same diet during lactation. No difference was observed in litter size at farrowing and piglet performance at weaning between treatments. Sows fed 25OHD3 diet had increased plasma concentrations of prolactin (P = 0.05) and tended to have increased estradiol concentrations (P = 0.09) at farrowing. Sows fed 25OHD3 diet tended to have higher dry matter and fat contents in milk on day 10 of lactation (P = 0.08), increased plasma calcium concentration in newborn piglets (P < 0.05), and proportions of tibia and femur to body weights (P < 0.05) in weaning piglets. Newborn piglets from sows fed 25OHD3 diet had increased crypt depth (P < 0.05), and decreased ratio of villus height to crypt depth (P < 0.05). Compared with the VD3 diet, sows fed the 25OHD3 diet tended to have more fecal Firmicutes (P = 0.09) and fewer Campylobacterota (P < 0.05) at farrowing, and had fewer Bacteroidota and Spirochaetota (P < 0.05) at the end of lactation. Moreover, the weaning piglets from sows fed 25OHD3 diet had a higher abundance of Pseudomonas (P < 0.05), and a lower abundance of Bacteroides, Megasphaera, CAG-873, and Olsenella (P < 0.05) in colonic chyme. We conclude that 25OHD3 supplementation in gestation sows improves milk composition, increases the blood calcium concentration of newborn piglets, the tibia and femur weight of weaned piglets, and alters the intestinal microbiota of both sows and piglets.