Regulation of Gut Antimicrobial Peptides and Cytokines Expression in Broiler Chicks Challenged by Campylobacter jejuni Lipopolysaccharides

ABSTRACT This study evaluated the effect of probiotics on antimicrobial peptides and cytokines’ mRNA synthesis in the proventriculus and cecum of broiler chicks exposed to Campylobacter jejuni lipopolysaccharides (LPS). The chicks were divided into two groups: the probiotic-supplemented group, which received 0.4% probiotics in their feed for seven days, and the control group, which did not receive probiotics. On the seventh day, both groups were further divided and exposed to either no LPS (0-LPS) or 1 µg LPS (1-LPS) (n=6 per group). Five hours post-LPS administration, tissue samples from the proventriculi and ceca were collected, and the expression of avian beta defensins (AvBDs), cathelicidins (CATHs), and proinflammatory cytokines was assessed via real-time PCR. The expression of CATH, AvBD4 and AvBD6 in the proventriculus, and CATH1, CATH3, AvBD2, AvBD4, AvBD6 and AvBD7 in the cecum was downregulated in the probiotic group compared to the control group following 1-LPS exposure. Probiotic upregulated the levels of IL6 and TNFSF15 in the cecum, and IL6 in the proventriculus after exposure to 1-LPS. This study concluded that Campylobacter LPS either downregulated or had no significant effect on AvBDs and CATHs expressions in probiotic-fed chicks. In addition, the innate immune response in the form of AvBDs, CATHs and cytokines may be modulated according to the nature of the pathogen and the supplemented probiotics.