Antimicrobial peptides against bacterial pathogens in aquatic and livestock systems: mechanisms, rational design, and translational barriers

Antimicrobial peptides (AMPs) are being investigated for bacterial-pathogen control in aquatic and livestock systems, but their translational evidence is uneven. This narrative review links membrane disruption, intracellular targeting, biofilm inhibition, and host-directed effects to the experimental systems that support each mechanism. Representative piscidins, defensins, cecropins, bacteriocins, and synthetic peptides are compared by assay endpoint and evidence tier. Target-animal infection studies include both protective and unsuccessful interventions, whereas in vitro activity, toxin-injury mitigation, and mammalian-model protection cannot independently establish veterinary efficacy. AMP-antibiotic interactions include synergy, indifference, and context-dependent antagonism, and resistance or cross-resistance can arise. Translation requires route-specific exposure, relevant host-cell safety assessment, and manufacturing feasibility. Biodegradation may limit environmental persistence while shortening effective exposure. AI tools can prioritize candidates, but their predictions require validation in the intended pathogen, animal species, and administration context.