Oral vaccination of young broilers with a liveTyphimurium vaccine reduces caecal and internal organ colonization following aInfantis challenge in a seeder-bird model.

Abstract

Poultry products are an important source of foodborneinfections in humans. Amongst these, the prevalence ofInfantis is rising. In this study, the protection efficacy of an authorized live-attenuatedTyphimurium vaccine againstInfantis, was examined using a seeder-bird model in broilers. Vaccinated birds displayed a significantly lower colonization ofInfantis bacteria in the caeca compared to the non-vaccinated counterparts (&#x2009;=&#x2009;0.017), with no significant differences observed in the spleen among the groups, three days post-infection. Thirty-two days post-infection, the disparity in averageInfantis concentration between all-vaccinated and non-vaccinated birds was significant in both caeca (&#x2009;=&#x2009;0.0003) and spleen (&#x2009;=&#x2009;0.0002). Interestingly, a third group, consisting of seeder birds that were not vaccinated but housed with vaccinated penmates, exhibited significantly lower. Infantis levels in both caeca (&#x2009;=&#x2009;0.0014) and spleen (&#x2009;<&#x2009;0.0001) compared to the non-vaccinated group. These findings underscore the potential of a live-attenuatedTyphimurium vaccine administered to 2-day-old chicks in conferring protection againstInfantis in broilers up to slaughter age.