# Intestinal Development in Wuzhishan Pigs at Different Growth Phases: Insights from Microbiome and Metabolomics

## TL;DR

This study explores how the intestines of Wuzhishan pigs develop over time, linking changes in gut microbes and metabolites to growth patterns.

## Contribution

The study provides new insights into the sequential changes in gut microbiota and metabolites during different growth phases of Wuzhishan pigs.

## Key findings

- Weaning stage showed immature intestinal function and higher opportunistic pathogens.
- Fattening stage had enhanced amino acid metabolism linked to increased Lactobacillus.
- Mature pigs showed elevated immune-related metabolites and vitamin B6 metabolism.

## Abstract

Wuzhishan pigs are an important indigenous Chinese breed with relatively slow growth. This study investigated intestinal development, gut microbiota, and metabolites across four growth stages. Intestinal function was immature at weaning, with a higher abundance of potential opportunistic pathogens and lower lipid metabolites. During fattening, amino acid metabolism was significantly enhanced, which was associated with increased abundance of Lactobacillus. In mature pigs, immune-related metabolites were elevated and enriched in vitamin B6 metabolism. These sequential changes in gut microbes and metabolites provide a basis for clarifying the mechanism underlying accelerated weight gain after the fattening stage. This study reveals intestinal developmental patterns in Wuzhishan pigs and supports improving their growth efficiency.

Wuzhishan pigs are a typical Chinese indigenous miniature pig breed, with thin skin and high amino acid content in muscle; slow weight gain and long feeding phases limit their value. As the primary digestive and absorptive organ, the intestine is crucial for growth, yet current studies on its development are limited. This study aimed to investigate intestinal physiological differences in Wuzhishan pigs across four phases (pre-weaning: 7, 14 days; weaning: 35, 38, 45 days; fattening: 70, 100 days; maturity: 180, 240 days) by evaluating intestinal morphology, digestive enzyme activity, gut microbiota diversity via 16S rRNA gene sequencing, and metabolite characteristics via metabolomic analysis. Results showed poor intestinal morphology and enzyme activity during weaning, significant ileal and colonic microbial diversity differences across phases, increased beneficial bacteria with age, and enriched opportunistic pathogens (Streptococcus, Romboutsia, Terrisporobacter) during weaning; weaning also had lower lipid metabolites, correlated with decreased Fusobacterium, Lactobacillus, and Muribaculaceae. Fattening enhanced amino acid metabolism, with increased Lactobacillus correlated with higher amino acids and muscle-related metabolites, while maturity increased immune-related metabolites (e.g., pyridoxine) in the vitamin B6 pathway. These results explain delayed rapid weight gain in Wuzhishan pigs and provide a theoretical basis for maintaining intestinal stability and production performance.