Maternal VD3 supplementation during gestation improves intestinal health and microbial composition of weaning piglets.

Vitamin D3 (VD3) has been reported to improve the reproductive performance of sows. This study was conducted to investigate the long-term effect of maternal VD3 supplementation during gestation on the intestinal health of piglets. Twenty-three Landrace × Yorkshire gilts were randomly allocated into two groups to receive one of the following two diets during gestation: basal diet (CON group, 800 IU VD3 per kg diet, n = 12) and VD3 supplemented diet (VD3 group, 2000 IU VD3 per kg diet, n = 11). All sows were then fed with the same diet during lactation. Results showed that maternal VD3 supplementation during lactation tended to decrease (p = 0.08) the body weight loss of sows during lactation compared to the CON group. Besides, the relative length and weight of the small intestine (SI) and the villus height of the duodenum and ileum in weaning piglets were much higher (p < 0.05) in the VD3 group than those in the CON group, though their body weight was not changed. Meanwhile, maternal VD3 supplementation significantly upregulated the expression levels of IGF-1, IGF-2R, VDR, GLUT-2 and CAT1 in the duodenum (p < 0.05), and increased the expression levels of IGF-1, IGF-1R, IGF-2R, VDR, Occludin, ZO-1, MUC2, PEPT1 and CAT1 (p < 0.05) in the jejunum of suckling piglets compared with the CON group. Besides, the concentration of SigA in the jejunum of suckling piglets was higher (p < 0.05) in the VD3 group than that in the CON group. In addition, maternal VD3 supplementation significantly increased the contents of short chain fatty acids and the relative abundance of Lactobacillus and Faecalibacterium (p < 0.05) in the feces of weaning piglets compared to the CON group. Moreover, the relative abundance of unidentified_Lachnospiraceae in the feces of weaning piglets tended to be higher (p = 0.05), while that of unidentified_Spirochaetaceae was lower (p < 0.05) in the VD3 group than those in the CON group. Taken together, maternal VD3 supplementation during gestation could improve the intestinal function and microbiota in suckling piglets.