# Impact of chitosan supplementation on metabolomic profiles and microbial community dynamics in total mixed ration silage and rumen fluid

## TL;DR

This study shows how adding chitosan to animal feed changes the gut microbes and chemical profiles in cows, potentially affecting digestion and health.

## Contribution

The study reveals specific microbial and metabolomic changes caused by chitosan in ruminant feed, identifying key biomarkers and microbial shifts.

## Key findings

- Chitosan increased L-valine levels in TMR silage, suggesting a potential biomarker.
- Amine compounds like Dibenzylamine rose in rumen fluid with chitosan supplementation.
- Microbial genera like Prevotella decreased, while Rikenellaceae_RC9_gut_group increased with chitosan.

## Abstract

This study aimed to investigate the effects of varying levels of chitosan supplementation in total mixed ration (TMR) silage on the abundance and dynamics of rumen microbial communities, as well as their associated metabolomic profiles.

Next-generation sequencing and liquid chromatography–high resolution mass spectrometry-based metabolomics were employed to assess alterations in rumen microbiota and metabolites composition in response to chitosan supplementation in TMR silage.

A total of 304 metabolites were identified in TMR silage, 144 of which had a variable importance in projection (VIP) scores greater than 1, marking them as distinguishing metabolites. Notably, chitosan supplementation increased L-valine levels, identifying it as a potential biomarker metabolite. In rumen fluid samples, 34 metabolites were identified, with 13 exhibiting VIP scores over 1, classifying them as key metabolite indicators. Chitosan supplementation significantly elevated amine compounds, particularly Dibenzylamine and N,N-Bis(2-hydroxyethyl) dodecanamide, in rumen fluid. The primary phyla affected by chitosan in TMR silage were Proteobacteria, Bacteroidota, and Firmicutes. Additionally, the genera Succinivibrionaceae_UCG-002 and Prevotella decreased with chitosan supplementation, whereas Rikenellaceae_RC9_gut_group exhibited increased abundance. Predominantly negative correlations were observed between rumen fluid metabolites (particularly amines and indoles) and microbial populations belonging to Bacteroidota and Firmicutes.

These findings indicate that chitosan supplementation alters rumen metabolic activity and reduced microbial diversity within the rumen.