The current study conducted to investigate the effects of a multi-strain commercial probiotic mix and prebiotic (isomaltooligosaccharide, IMO) on broiler performance parameters, cecal microbiota composition, and protection against challenge with avian pathogenic Escherichia coli (APEC) O78. For this purpose, 101-day-old Cobb chicks were randomly allocated into four experimental groups (G)-G01: basal diet, G02: basal diet and challenged with E. coli O78 at 28 days old, G03: basal diet with probiotic mix and challenged with E. coli O78 at 28 days old, and G04: basal diet with IMO and challenged with E. coli O78 at 28 days old. Results showed that weekly body weights in G03 were heavier (P < 0.05) than those of G01 and G02 at the fourth and fifth week. The body gain at the fourth and fifth week was higher (P < 0.05) in G03 than those of the other groups. The hot carcass weight (g) was significantly higher in broiler chickens kept in G03 and G04 compared with those in the control groups (G01 and G02). The probiotic mix and IMO significantly increased the total lactobacilli and total lactobacilli-enterococci populations in the ceca of treated broilers, respectively compared with those in the control groups. The treated broilers (G03 and G04) also showed lower mortality percentage and E. coli recovery rates the liver and spleen than those in G02. It was concluded that probiotic mix or IMO significantly improved the growth performance and modulated the intestinal microbiota of broiler chickens challenged with APEC O78.
Keywords: Broilers; Escherichia coli O78; Intestinal microbiota; Isomaltooligosaccharide; Probiotic.