Effects of synbiotic supplementation as an antibiotic growth promoter replacement on cecal Campylobacter jejuni load in broilers challenged with C. jejuni

Abstract

Synbiotic supplementation alters gut microbiota via competitive exclusion, improving production performance, decreasing cecal Campylobacter jejuni load and colonization, and improving immunological responses while offering an alternative to antibiotic growth promoters in poultry production. This study aimed to determine effects of synbiotic supplementation as an antibiotic replacement in C. jejuni challenged broilers. 336 one-day-old broiler chicks were distributed into four treatment groups: Control, Synbiotic, Antibiotic + Challenge, and Synbiotic + Challenge, with six replicate pens per treatment. Antibiotic (Virginiamycin) and synbiotic (PoultryStar® Me) were supplemented in feed 20 mg/kg and 20 g/1000 birds/day, respectively. At 21 days of age, birds were orally inoculated with PBS or 1 × 10 8 CFU/bird C. jejuni . Feed intake and body weight were measured on a weekly basis. On 3, 7, and 14 dpi, intestinal permeability, anti- C. jejuni IgA bile concentration, C. jejuni content (ceca, ileal tissue, and liver), splenocyte MNC nitric oxide production, cecal tonsil CD4 + :CD8 + and CD4 + :CD25 + ratios, and cecal cytokine immune gene and tight junction protein expression were quantified and statistically analyzed. We found that synbiotic supplementation limited cecal C. jejuni colonization more effectively than antibiotic supplementation, upregulated tight junction protein expression, and positively altered cytokine and chemokine gene expression in response to challenge. We conclude that synbiotic supplementation decreases C. jejuni loads in broilers and beneficially modulates the immune response to C. jejuni challenge, compared to antibiotic supplementation, and that synbiotics can be applied to replace antibiotic growth promoter usage during poultry C. jejuni infection.