Dietary Full-Fat Rice Bran or Glucose Regulates Bile Acid Circulation, Colonic Microbiota, and Short-Chain Fatty Acids in Pigs During Chronic Cold Stress

Chronic cold stress is a severe test that animals in cold regions have to face during winter. However, the lack of precise dietary adjustments for animals in cold regions represents a significant gap in addressing their nutritional needs. Full-fat rice bran is one of the feed materials rich in protein, lipids, dietary fiber, and antioxidant-active substances. Glucose is the most common quick energy supply. We determined dietary full-fat rice bran and glucose can improve the growth and health of cold-exposed pigs. A total of 18 Yorkshire pigs were randomized to one of three treatment groups (basal diet, full-fat rice bran diet (20%), and glucose diet (10%)) for 22 d to evaluate the effects of full-fat rice bran and glucose on growth performance, antioxidants, microbiomes, and bile acid circulation in cold-exposed pigs. The results showed that dietary full-fat rice bran decreased the average daily feed intake (<i>p</i> < 0.05), increased superoxide dismutase (SOD) activity in plasma (<i>p</i> < 0.05), and decreased <i>Rikenellaceae_RC9_gut_group</i> and <i>Campylobacter</i> in the colon microbiota of cold-exposed pigs (<i>p</i> < 0.05). Dietary glucose improved the growth performance of cold-exposed pigs and decreased the abundance of <i>Prevotellaceae_NK3B31_group</i> (<i>p</i> < 0.05) in the colon microbiota of cold-exposed pigs. Dietary full-fat rice bran and glucose both downregulated the abundance of <i>Alloprevotella</i>, <i>Bradymonadales</i>, and <i>Erysipelotrichaceae</i> in colon microbiota (<i>p</i> < 0.05), promoted the production of SCFAs, and activated the FXR-CYP7A1 signaling pathway. Dietary full-fat rice bran or glucose promoted fecal excretion of bile acids. This study demonstrated that dietary supplementation with full-fat rice bran or glucose can improve the colonic microbiota structure and SCFA levels in cold-exposed pigs. When comparing the two dietary strategies, the glucose-supplemented diet is more beneficial to the growth performance of cold-exposed pigs, while the full-fat-rice-bran-supplemented diet is more conducive to enhancing the function of their antioxidant system. Additionally, dietary supplementation with full-fat rice bran or glucose can also regulate the bile acid circulation in pigs, thereby enhancing their cold adaptation ability.