Reduction of Salmonella enterica var. Enteritidis colonization and invasion by Bacillus cereus var. toyoi inclusion in poultry feeds

The effect of continuously feeding the probiotic microorganism Toyocerin to birds inoculated with Salmonella Enteritidis field-isolated strains on Salmonella Enteritidis prevalence, and performance variables were studied in 2 experiments. The experiments were performed with 1) broiler chickens in floor pens until slaughter 42 d of age, challenge was performed on d 3, 7, or 14 with 2 x 10⁶ cfu per chick, and 2) Single Comb White Leghorn chickens in cages until 28 d of age, challenge was performed on d 7 with 10⁸ cfu per chick. The inclusion of Toyocerin in feed of inoculated broiler chickens did significantly (P < 0.05) improve ADG (by 3.4 g), BW (by 141 g), and feed conversion ratio (by -0.060 kg/kg) at the end of the trial at 42 d compared with inoculated and untreated birds. At the end of the trial at 42 d, the slaughter age, 42% of untreated birds were still positive for Salmonella, whereas Salmonella was not detected in Toyocerin-treated birds. In Leghorn chickens, at 3 wk after inoculation (the end of the trial), only 38% of birds from the Toyocerin-treated groups were Salmonella-positive, whereas 63% of birds were still Salmonella-positive in the untreated control treatment. No significant differences were detected in performance variables in Leghorn chickens. The results of the present experiments indicate that feeding Toyocerin reduced the prevalence of Salmonella in poultry and in the case of broiler chickens also significantly improved performance variables at slaughter age.