# Metabolomic and metagenomic insights into WFBG-mediated regulation of gut microbiota and metabolism in broilers

## TL;DR

This study explores how wet-fermented brewer's grain affects gut microbiota and metabolism in chickens, identifying key biomarkers and optimal usage levels.

## Contribution

The study provides novel insights into the molecular mechanisms of WFBG in regulating gut microbiota and metabolism in broilers.

## Key findings

- WFBG supplementation altered gut microbiota composition, including changes in Ligilactobacillus, Olsenella, and Blautia.
- Serum metabolomic analysis identified 546 differentially expressed metabolites linked to intestinal development pathways.
- Integrative analysis revealed correlations between specific bacteria and metabolites like quercetin and deoxycholic acid derivatives.

## Abstract

The steady state of gut microbiota is a key factor in regulating the growth of broilers. The regulatory role of wet-fermented brewer’s grain (WFBG) in broiler gut development and microbiota is still elusive. In this study, non-targeted metabolomics and 16S rRNA sequencing analysis were used to investigate the effects of WFBG supplementation on serum metabolites and gut microbiota in 42-day-old broilers. Serum metabolomic analysis identified 546 differentially expressed metabolites (DEMs), with GO and KEGG enrichment analyses showing that specific DEMs were enriched in intestinal development-related pathways, including phenylalanine, tyrosine, tryptophan biosynthesis, and alpha-linolenic acid metabolism. 16S rRNA sequencing analysis showed significant intergroup differences in the relative abundances of Ligilactobacillus, Olsenella, Erysipelatoclostridium, and Blautia at the genus level in broiler gut microbiota between the control and WFBG groups. Integrative analysis of 16S rRNA sequencing and non-targeted metabolomics demonstrated that bacterial genera, including Streptococcus and Proteus, were positively correlated with N6,N6-dimethyllysine and quercetin but negatively associated with 18 DEMs, such as 4-methylbenzenesulfonic acid and deoxycholic acid derivatives. Furthermore, we identified potential biomarkers associated with intestinal development induced by 20% WFBG supplementation. Our findings suggest that the maximum recommended inclusion level of WFBG in broiler feed should not exceed 20%. This study provides novel insights into the molecular mechanisms underlying fiber utilization and intestinal maturation in broilers.

This study investigated the regulatory mechanism of wet-fermented brewer's grain (WFBG) on gut development and microbiota in commercial broilers. Through integrated 16S rRNA sequencing and non-targeted metabolomic analysis, the study not only identified differential gut microbiota, serum metabolites, as well as their correlations, but also discovered potential biomarkers associated with intestinal development induced by 20% WFBG and clarified the maximum recommended inclusion level of WFBG (≤20%). This not only filled the gap in the molecular mechanism underlying WFBG-mediated regulation of fiber utilization and intestinal maturation in broilers but also provided a theoretical basis and practical guidance for the resource utilization of agricultural by-products, precision feeding of broilers, and intestinal health monitoring.