Ellagic acid in poultry nutrition: emerging roles in gut health, immunity, and sustainable production.

Ellagic acid (EA), is a naturally occurring polyphenolic compound abundant in pomegranate, berries, walnuts, and various agro-industrial by-products, and has attracted increasing interest as a potential phytogenic feed additive for poultry. Its importance arises from the need for effective natural alternatives to antibiotic growth promoters that can simultaneously support bird health, productivity, and production sustainability. This review synthesizes evidence from peer-reviewed studies identified through systematic searches of major scientific databases using combinations of keywords related to EA, poultry, gut health, immunity, oxidative stress, inflammation, growth performance, meat quality, and sustainable production. Relevant peer-reviewed studies were selected based on their direct relevance to EA-mediated physiological, intestinal, immunological, and productive responses in poultry. Literature indicates that EA exerts antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory activities through regulation of oxidative stress responses, inflammatory signaling, intestinal barrier function, and gut microbial communities. Emerging evidence further suggests potential benefits for growth performance, feed efficiency, meat quality, and product stability, while nutrigenomic studies indicate that EA can modulate genes involved in immunity, metabolism, antioxidant defense, and intestinal function. However, its practical application is constrained by limited bioavailability, variable responses, dose optimization, and insufficient long-term evidence. Therefore, this review aims to critically evaluate the mechanistic basis and poultry-specific evidence for EA as a phytogenic feed additive, with particular emphasis on gut-microbiota interactions, immune regulation, oxidative stress and inflammation, productive performance, and highlights the prospects and limitations for sustainable poultry production.