Sessions

Largely driven by the overuse of antibiotics in livestock production, antimicrobial resistance (AMR) is a critical threat to both veterinary and public health. Alternatives to conventional antibiotics are urgently needed, especially in poultry production, where intestinal integrity is central to maintaining productive performance and disease resistance. Antimicrobial peptides (AMPs) have emerged as promising candidates due to their ability to both exert direct antimicrobial activity and modulate host gut health in various ways, including the reinforcement of tight junction (TJ) connections. However, a vast majority of the peptides have yet to be investigated regarding their effects on TJ protein expression in poultry cells. Thus, this study investigated the impact of two AMPs, Cecropin A and Pap12-6, on cell viability, occludin and claudin-3 expression, as well as transforming growth factor (TGF)-β1 levels in chicken ileal explant cultures. The last parameter was selected based on its association with the expression levels of TJ proteins.

Explant cultures derived from a 3-week-old male Ross-308 broiler were treated with low and high concentrations of Cecropin A (3.125 and 6.25 µg/ml, respectively) and Pap12-6 (25 and 50 µg/ml, respectively). Cellular metabolic activity and extracellular lactate dehydrogenase (LDH) activity were assessed to determine cytotoxicity, while chicken-specific ELISA assays quantified claudin-3, occludin, and TGF-β1 levels.

Results showed no significant differences in cell viability across treatment groups, indicating that neither peptide exerted cytotoxic effects. Pap12-6 at a low concentration significantly upregulated occludin expression, whereas high concentrations of both Cecropin A and Pap12-6 significantly increased claudin-3 expression. TGF-β1 levels remained unchanged, and no correlation was observed between the cytokine and TJ proteins. However, a strong positive correlation was detected between claudin-3 and occludin, suggesting coordinated barrier regulation.

In conclusion, Cecropin A and Pap12-6 appear to support intestinal barrier function without compromising cellular viability, highlighting their potential as safe alternatives to antibiotics in poultry production. By enhancing TJ protein expression, these peptides may contribute to improved gut integrity and resilience, thereby reducing reliance on conventional antimicrobials and supporting sustainable production systems in the future.