Comparative Meta‐Analysis of Antimicrobial Peptides in Aquatic and Terrestrial Livestock Species

ABSTRACT Antimicrobial peptides (AMPs) are increasingly used as feed additives to enhance the growth, health, and immunity of farmed animals. However, their effectiveness varies across species, dosages, and feeding durations, and an integrated assessment is lacking. This study performed a global meta‐analysis to quantify the effects of dietary AMPs supplementation on growth performance, blood metabolites, immune response, intestinal morphology, and gut microbiota diversity. A total of 58 peer‐reviewed studies comprising 926 effect sizes were included from five animal taxa, encompassing 29 species. Effect sizes were calculated using Hedges' g , and meta‐regression was applied to explore dose‐response relationships. Results showed that AMPs supplementation significantly improved growth performance and blood metabolite profiles, particularly in omnivorous livestock, such as chickens and pigs. Conversely, the impact of AMPs on the gut microbiota diversity of aquatic animals was less pronounced than in terrestrial livestock, likely attributable to differences in habitat and physiological characteristics. Regarding supplementation strategies, a 60‐day regimen of 1000 mg/kg of AMP produced the most favorable outcomes in aquatic species. For livestock, a period of at least 30 days with doses above 250 mg/kg yielded substantial benefits. This study offers empirically substantiated confidence for the utilization of AMPs as efficacious substitutes for antibiotics. These findings contribute to the development of targeted, species‐specific feeding strategies for sustainable and efficient animal production.