Non-digestible polysaccharides are of great significance to human and animal intestinal health. Cellulose, arabinoxylan, β−glucan and glucomannan were selected in the present study to investigate the fermentation characteristics and fiber-degrading enzyme kinetics by inoculating pig fecal microbiota in vitro. Our results showed that fermentation of arabinoxylan and β-glucan produced the highest amount of acetate and lactate, respectively. The abundance of Prevotella_9 was the highest in β-glucan group and positively correlated with lactate and acetate. Glucomannan fermentation produced the highest amount of butyrate, and the abundance of Lachnospiraceae_XPB_1014_group and Bacteroides were the lowest. A significant negative correlation was found between Lachnospiraceae_XPB_1014_group, Bacteroides and butyrate. Exo-β-1,4-xylanase had the highest activity at 24 h during arabinoxylan fermentation. The activity of β-glucosidase and β-mannosidase at 36 h were higher than those at 15 h in the glucomannan group. The abundance of Prevotella_9 was positively correlated with β-glucosidase while Lachnospiraceae_XPB_1014_group and Bacteroides were negatively correlated with β-xylosidase. Our findings demonstrated the β-glucan and arabinoxylan promote proliferation of Prevotella_9, with the preference to secret β-glucosidase, β-mannosidase and the potential to produce lactate and acetate. Butyrate production can be improved by inhibiting the proliferation of Lachnospiraceae_XPB_1014_group and Bacteroides, which have the lack of potential to secret β-xylosidase.

This study was conducted to evaluate the effects of 25-hydroxyvitamin D₃ (25(OH)VD₃) and Vitamin D₃ (VD₃) 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 VD₃ (negative control, NC), NC + 100 ppm colistin sulfate (positive control, PC), NC + 2000 IU VD₃ (VD₃) and NC + 2000 IU 25(OH)VD₃ (25(OH)VD₃)_. The results showed that 25(OH)VD₃ improved the growth performance, bone quality and antioxidase activity of piglets compared with the other groups. Meanwhile, 25(OH)VD₃ up-regulated ileal mRNA expressions of tight junction proteins and host defense peptides. The VD₃ group had an increased intestinal sIgA content and mRNA expression of pBD-1 compared with the NC group. Both groups of VD₃ and 25(OH)VD₃ altered the microbial β-diversity compared with the NC group, and 25(OH)VD₃ increased ileal concentrations of acetate and butyrate. In conclusion, our findings indicated that a regular dosage of 2000 IU VD₃ in the weaned piglets’ diet did not achieve optimal antioxidant capacity and immune function. 25(OH)VD₃ had better growth performance than VD₃ at the same inclusion level, which is associated with the improved intestinal integrity and antioxidant capacity.