# Fermented marigold meal enhances muscle nutrition and flavor in white feathered broilers via gut microbiota modulation

## TL;DR

Fermented marigold meal improves the nutrition and flavor of chicken meat by changing gut bacteria in broilers.

## Contribution

First evaluation of fermented marigold residue as a feed additive for enhancing broiler meat quality.

## Key findings

- Fermented marigold meal increased non-essential amino acids and n-3 PUFAs in broiler breast muscle.
- Gut microbiota was enriched with beneficial bacteria like Lactobacillus and Parabacteroides.
- Key aroma compounds in meat were elevated due to microbiota changes from the fermented feed.

## Abstract

Marigold (Tagetes erecta L.) residue, a by-product of industrial lutein extraction, is rich in carotenoids and polyphenols, offering potential as a poultry feed additive. This study employed Lactobacillus plantarum for solid-state fermentation of marigold meal and evaluated dietary inclusion (5 % or 10 %) in broilers for 42 days. Fermented marigold meal had no significant effects on growth performance or basic meat quality (pH, color, water-holding capacity) but improved breast muscle composition by increasing non-essential amino acids (e.g., glutamate, GABA), n-3 PUFAs, and PUFA/SFA ratio, while reducing MUFAs. 16S rRNA sequencing revealed enrichment of beneficial bacteria (Parabacteroides, Lactobacillus) and higher butyric acid levels. GC–MS identified 171 volatile compounds, with elevated key aroma compounds (e.g., 2(3H)-furanone, Geranylacetone) in marigold-fed groups, linked to altered microbiota. Fermented marigold meal enhances meat nutrition and flavor through gut microbiota-mediated pathways, providing a sustainable approach for high-value utilization of agricultural by-products.

•First evaluation of fermented Tagetes erecta residue for animal feed application.•Fermentation enriched total flavonoids, phenolics, sugars, and protein in marigold residue.•Dietary fermented residue improved broiler muscle GABA and n-3 PUFA content.•Gut microbiota was reshaped, increasing Lactobacillus and SCFA (butyrate) levels.•A “microbiota–metabolism–muscle deposition” mechanism was proposed and verified.

First evaluation of fermented Tagetes erecta residue for animal feed application.

Fermentation enriched total flavonoids, phenolics, sugars, and protein in marigold residue.

Dietary fermented residue improved broiler muscle GABA and n-3 PUFA content.

Gut microbiota was reshaped, increasing Lactobacillus and SCFA (butyrate) levels.

A “microbiota–metabolism–muscle deposition” mechanism was proposed and verified.