Preventive effects of synbiotic supplementation againstEnteritidis infection in broiler chickens.

Abstract

The restriction of antibiotics as growth promoters in poultry has intensified the search for alternative strategies to control enteric pathogens. This study aimed to develop a multi-strain probiotic composed ofCRL 1385,subsp.CRL 1417, andCRL 1453, formulate a synbiotic by combining this mixture with raffinose and molasses, and evaluate their preventive efficacy againstinfection in broiler chicks. Strain compatibility was assessed using a well-diffusion assay with cell-free supernatants, confirming absence of antagonism among strains.co-culture assays demonstrated a clear bactericidal effect, with inactivation ofEnteritidis PT4 1222 andGallinarum INTA 91/A1.assays using intestinal explants showed that pre-treatment with probiotic or synbiotic formulations significantly reducedadhesion, suggesting that the primary protective mechanism involved inhibition of pathogen attachment to epithelial surfaces. Forevaluation, chicks received daily treatments from day 1 post-hatch and were challenged via crop injection on day 3. Synbiotic administration significantly reducedEnteritidis infection rates (30% vs. 100% in controls), while all treatments failed to reduceGallinarum prevalence. These findings highlight the potential of early-life synbiotic administration as a sustainable strategy to preventEnteritidis infections in poultry.