Abstract
Increasing antibiotic resistance is a matter of grave concern for consumers, public health authorities, farmers, and researchers. Antimicrobial peptides (AMPs) are emerging as novel and effective non-antibiotic tools to combat infectious diseases in poultry. In this study, we evaluated six avian AMPs including 2 truncated cathelicidins, [CATH-1(6–26) and CATH-2(1–15)], and 4 avian β-defensins (ABD1, 2, 6 and 9) for their bactericidal and immunomodulatory activities. Our findings have shown CATH-1(6–26) and ABD1 being the two most potent avian AMPs effective against Gram-positive and Gram-negative bacteria investigated in these studies. Moreover, CATH-1(6–26) inhibited LPS-induced NO production and exhibited dose-dependent cytotoxicity to HD11 cells. While, ABD1 blocked LPS-induced IL-1β gene induction and was non-toxic to HD11 cells. Importantly, in ovo administration of these AMPs demonstrated that ABD1 can offer significant protection from early chick mortality (44% less mortality in ABD1 treated group versus the control group) due to the experimental yolk sac infection caused by avian pathogenic Escherichia coli. Our data suggest that in ovo administration of ABD1 has immunomodulatory and anti-infection activity comparable with CpG ODN. Thus, ABD1 can be a significant addition to potential alternatives to antibiotics for the control of bacterial infections in young chicks.
Highlights
Increasing antibiotic resistance is a matter of grave concern for consumers, public health authorities, farmers, and researchers
Working stocks for in vitro and in ovo experiments were prepared by dissolving lyophilised powder of the linear forms of peptides in LPS-free water
CATH-1(6– 26), CATH-2(1–15), and ABD1 have higher pIs compared with three other ABDs
Summary
Increasing antibiotic resistance is a matter of grave concern for consumers, public health authorities, farmers, and researchers. Five peptides [CATH-2(1–15), ABD1, 2, 6, 9] have not shown any significant effect on the growth and metabolic activity of HD11 cells. 0 CATHC-1A(6T-H2-62)(1-15)ABD1ABD2ABD6ABDC9ontrol differences in gene expression of above-mentioned chemokines in cells stimulated with other peptides and the control groups (Fig. 4).
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