Caffeic Acid as a Promising Natural Feed Additive: Advancing Sustainable Aquaculture.

Caffeic acid (CA), a plant-derived phenolic compound, is emerging as a promising natural feed additive for sustainable aquaculture. Its growth-promoting, immunomodulatory, and antimicrobial activities suggest utility as an alternative that diminishes antibiotic use in fish farming. Evidence across multiple species indicates improvements in innate immune responses, enhanced antioxidant capacity, and increased survival during pathogen challenge. Nevertheless, adoption remains limited by unresolved questions regarding optimal inclusion levels, species-specific physiological responses, interactions with other dietary components, and effects on the gut microbiota. This review synthesizes current research on CA, critically evaluates its functional roles in aquaculture, and assesses its relevance to sustainable production. Priorities for future work include elucidating mechanisms of action, conducting cross-species dose-response studies, standardizing dosing protocols, clarifying microbiome effects, and evaluating economic feasibility for large-scale use. Addressing these gaps will be essential to realize the full potential of CA as a functional feed additive in sustainable aquaculture systems.