# Multi‐Omics Reveals Phenethyl Acetate and Its Producer Lactiplantibacillus plantarum as Key Drivers of Enhanced Palatability in Alfalfa Silage

## TL;DR

This study shows that using Lactiplantibacillus plantarum and phenethyl acetate together improves the flavor and palatability of alfalfa silage, leading to higher feed intake in sheep.

## Contribution

The study introduces a novel strategy for synergistic fermentation using Lactiplantibacillus plantarum and phenethyl acetate to enhance silage flavor and feed intake.

## Key findings

- Lactiplantibacillus plantarum and phenethyl acetate together significantly improved silage fermentation quality and feed intake.
- Key flavor compounds like phenylethyl alcohol and β-damascenone were increased with Lactiplantibacillus plantarum and phenethyl acetate.
- Specific enzymes from Lactiplantibacillus plantarum played a crucial role in flavor compound formation during fermentation.

## Abstract

High‐quality silage enhances palatability and feed intake; however, the effects of co‐fermentation with flavouring agents and lactic acid bacteria (LAB) on its flavour quality, core microbiota, and taste‐active amino acids remain unclear. This study investigated the effects of fermentation using Lactiplantibacillus plantarum (LP) alone or in combination with phenethyl acetate (LPP) on the flavour profile of alfalfa silage and its subsequent influence on feed intake. Both LP and LPP significantly improved fermentation quality versus control (CK), with markedly higher feed intake—LP > CK and LPP > LP. Key flavour compounds, including dimethyl trisulfide, 4‐ethylphenol and β‐damascenone, were significantly increased in the LP alone group. Contrarily, essential taste‐related amino acids including aspartic acid, alanine, proline, histidine, isoleucine, and valine were decreased, except for arginine. These metabolic shifts collectively contributed to enhanced feed intake. The addition of LPP increased phenylethyl alcohol, benzyl alcohol and hexanal, and decreased arginine, contributing to enhanced palatability. Aryl alcohol dehydrogenase, proline aminopeptidase, histidine dehydrogenase, and branched‐chain amino acid transaminase from LP played a crucial role in the formation of phenylethyl alcohol, proline, histidine and isoleucine during fermentation. These results provide insights into how LAB and flavouring agents jointly regulate flavour development in high‐quality alfalfa silage.

The quality and flavour profile of silage affect its palatability and the feed intake of ruminants. This study offers a novel strategy for optimising the synergistic fermentation of Lactiplantibacillus plantarum and phenylethyl acetate, thereby enhancing alfalfa silage flavour quality and promoting sheep feed intake.