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

## TL;DR

This study shows that adding full-fat rice bran or glucose to pig diets helps them cope with cold stress by improving gut health and antioxidant activity.

## Contribution

The study introduces dietary strategies using full-fat rice bran and glucose to regulate gut microbiota and bile acid circulation in cold-stressed pigs.

## Key findings

- Full-fat rice bran reduced feed intake and increased antioxidant activity in cold-exposed pigs.
- Glucose improved growth performance and altered gut microbiota in cold-stressed pigs.
- Both diets promoted short-chain fatty acid production and regulated bile acid excretion.

## Abstract

Chronic winter cold stress challenges animal husbandry in cold regions, with insufficient precise dietary adjustments for animals’ specific nutritional needs. To address this, 18 Yorkshire pigs were randomly divided into three groups (basal diet, full-fat rice bran diet, glucose diet) for a 22-day cold exposure experiment, to assess the two diets’ effects on pigs’ growth performance, antioxidant capacity, gut microbiota, and bile acid circulation. Key results: The full-fat rice bran diet reduced cold-exposed pigs’ average daily feed intake, increased plasma superoxide dismutase activity, and lowered colonic Rikenellaceae_RC9_gut_group and Campylobacter abundance. The glucose diet improved growth performance and decreased colonic Prevotellaceae_NK3B31_group abundance. Both diets reduced colonic Alloprevotella, Bradymonadales, and Erysipelotrichaceae abundance, promoted short-chain fatty acid production, activated the Farnesoid X receptor signaling pathway, and increased fecal bile acid excretion. In conclusion, dietary full-fat rice bran or glucose regulates growth performance, antioxidant capacity, bile acid circulation, and gut microbiota in chronically cold-stressed pigs, providing a new basis for resolving cold-induced adverse effects via nutritional regulation.

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 (p < 0.05), increased superoxide dismutase (SOD) activity in plasma (p < 0.05), and decreased Rikenellaceae_RC9_gut_group and Campylobacter in the colon microbiota of cold-exposed pigs (p < 0.05). Dietary glucose improved the growth performance of cold-exposed pigs and decreased the abundance of Prevotellaceae_NK3B31_group (p < 0.05) in the colon microbiota of cold-exposed pigs. Dietary full-fat rice bran and glucose both downregulated the abundance of Alloprevotella, Bradymonadales, and Erysipelotrichaceae in colon microbiota (p < 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.