# Functional Effects of Dietary Grape By-Products on Rabbit Health, Performance, and Meat Quality

## TL;DR

This review explores how grape by-products can improve rabbit health, performance, and meat quality when used as feed additives.

## Contribution

The paper provides a synthesis of functional effects of grape by-products in rabbit nutrition and identifies practical inclusion ranges and research gaps.

## Key findings

- Moderate inclusion of grape by-products enhances antioxidant capacity and supports physiological resilience in rabbits.
- Grape by-products improve meat oxidative stability without consistently impairing growth or digestibility.
- Benefits are more evident under environmental stress conditions, but excessive inclusion may impair nutrient utilization.

## Abstract

Rabbit production is valued for efficiency and high-quality meat but faces challenges related to health, feed utilization, and meat stability. Meanwhile, the wine industry generates substantial grape by-products (GBPs), including pomace, seeds, skins, and stalks, which are rich in bioactive compounds yet underutilized. This review synthesizes current evidence on the functional roles of GBPs in rabbit nutrition beyond nutrient supply. It evaluates effects on growth performance, blood health and immune status, growth performance, reproduction, and meat quality. Moderate inclusion levels generally enhance antioxidant capacity, support physiological resilience (especially under heat stress), and improve meat oxidative stability without consistently impairing growth or digestibility. However, responses depend on by-product type, processing method, inclusion level, and production stage. Constraints include high fiber, tannins, compositional variability, and safety considerations. This review identifies practical inclusion ranges, mechanistic insights, and research gaps to support sustainable integration of GBPs into rabbit feeding systems.

The increasing global demand for animal-source protein underscores the importance of sustainable livestock systems, including commercial rabbit production. Rabbits are valued for their short production cycle, high prolificacy, efficient feed utilization, and favorable meat quality. In parallel, agro-industrial by-products are being explored as functional feed ingredients to improve efficiency and reduce environmental impact. Grape by-products (GBPs), including pomace, seeds, stalks, and derived extracts, are rich in polyphenols, dietary fiber, and lipid bioactives with potential physiological benefits. This scoping review synthesizes current evidence regarding the effects of GBPs on rabbit health, growth performance, nutrient digestibility, reproductive function, and meat quality. Available studies indicate that moderate dietary inclusion can enhance antioxidant status, support immune function, modulate gut fermentation, and improve meat oxidative stability without consistently compromising growth performance when appropriately formulated. Benefits appear particularly evident under environmental stress conditions. However, outcomes vary according to inclusion level, processing method, and physiological stage, and excessive inclusion may impair nutrient utilization due to fiber and tannin content. Overall, this synthesis identifies functional mechanisms, practical feeding considerations, and key knowledge gaps to inform evidence-based application of GBPs in sustainable rabbit nutrition.