# Fermented Rice Bran Enhances Rabbit Meat Quality and Nutritional Value via Metabolic Reprogramming and Enriched Nutrient Profiles

## TL;DR

Fermented rice bran improves rabbit meat quality by boosting nutrients and changing metabolism, offering a sustainable feed option.

## Contribution

The study reveals molecular mechanisms by which fermented rice bran enhances meat quality through gut-liver-muscle interactions.

## Key findings

- FDRBM improved meat water-holding capacity and essential amino acid content.
- FDRBM upregulated genes linked to oxidative muscle fibers and lipid metabolism.
- FDRBM enhanced ileum antioxidant capacity and reprogrammed liver metabolism.

## Abstract

To enhance sustainable meat production, this study addressed a critical gap in rabbit nutrition by evaluating fermented de-oiled rice bran meal (FDRBM) as a cost-effective substitute for maize. The study investigates the replacement of conventional ingredients with unfermented (UFDRBM) and fermented de-oiled rice bran meal (FDRBM) in growing rabbit diets and evaluates growth performance, carcass characteristics, meat quality, amino acid profile, and fatty acid composition. The novelty of this study lies in its integrated approach, which reveals molecular correlates linking the FDRBM diet and observed phenotypic improvements. These enhancements are attributed to a cascade of biological events, beginning with improved antioxidant capacity in the gut, leading to metabolic reprogramming in the liver, and culminating in a favorable shift in muscle fiber-type composition. The FDRBM diet also enhanced the nutritional value of the meat by improving its amino and fatty acid profiles. Ultimately, these findings are relevant and timely, particularly in the context of sustainable feed resources, byproduct utilization, and meat quality improvement in rabbit production.

Background: The valorization of sustainable feed ingredients such fermented de-oiled rice bran meal (FDRBM) is crucial; however, the molecular mechanisms driving its benefits remain unclear. This study addresses this gap by investigating FDRBM as a dietary substitute for maize in rabbits to determine its effects on meat quality and underlying gut–liver axis communication. Methods: In an eight-week trial, New Zealand White rabbits were assigned to a control diet or the basal diet with a 20% substitution of either unfermented de-oiled rice bran (UFDRBM) or FDRBM. Post-trial, the researchers analyzed carcass traits, meat quality, and nutritional composition. A multi-omics approach integrates gene expression data from the ileum and muscle with liver metabolomics to model coordinated biological responses. Results: Although growth performance was similar, the FDRBM diet significantly improved meat quality by enhancing water-holding capacity and increasing essential amino acids (p < 0.05). Mechanistically, these improvements were associated with the upregulation of genes associated with oxidative muscle fiber (Tnnc1) and lipid metabolism. Analysis of the gut–liver axis revealed that FDRBM enhanced ileum antioxidant capacity, which coincided with profound reprogramming of liver metabolism (p < 0.01 *), identifying C17-sphinganine as a differential metabolite. Conclusion: This study provides novel insights into the mode of action of FDRBM, suggesting that it enhances rabbit meat quality in part by modulating metabolic gene expression and is associated with coordinated molecular changes across the gut–liver axis.