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

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.