Impact of a Postbiotic Containing Saponin, with or without Vaccination, on the Mitigation of Colibacillosis in Broilers Challenged with Avian Pathogenic Escherichia coli Serotype O78

Avian pathogenic Escherichia coli (APEC) cause colibacillosis in commercial poultry resulting in significant flock health and economic burden. Evolving production practices and antimicrobial resistance may challenge traditional colibacillosis prevention and management, emphasizing the need for non-antibiotic solutions promoting resiliency against or amelioration of infections. This study evaluated the effect of a feed additive prototype (Diamond V, Cedar Rapids, IA) containing a Saccharomyces cerevisiae fermentation product with a Quillaja saponaria ingredient (SCFP+), alone or in combination with vaccination, to ameliorate the severity of clinical colibacillosis in broilers intratracheally challenged with APEC O78 at day 28. Necropsy on days 35 and 42 included lesion scoring for perihepatitis, pericarditis, and air sacculitis with sample collections from liver, lung, heart and airsac tissues for microbiological analysis. All treatment groups resulted in numerical improvements in mean lesion scores and livability when compared to the challenged control during acute infection at day 35. SCFP+ treatment alone resulted in mean lesion score improvements equivalent to or slightly enhanced when compared to the vaccine alone and co-administration did not reveal any adverse effects. SCFP+ application in feed was observed to have some corresponding reductions in APEC tissue loads. Select blood cytokine levels (pg/mL) were generally lower in all treated groups. By day 42, lesion scores and microbiological data suggested live birds had largely recovered from challenge. This study indicates the SCFP+ prototype, alone or in combination with vaccination, may be a viable, non-antibiotic solution to support reduction in the severity of clinical colibacillosis in broilers.