Propionibacterium freudenreichii freudenreichii B3523 reduces cecal colonization and internal organ dissemination of multidrug-resistant Salmonella Heidelberg in finishing turkeys

Previously, we reported that a dairy-originated probiotic bacterium, Propionibacterium freudenreichii subsp. freudenreichii B3523 (PF) reduced cecal colonization of multidrug-resistant Salmonella enterica serovar Heidelberg (SH) in poults (2-wk-old) and growing (7-wk-old) turkeys. In the present study, we validated the antibacterial potential of PF in finisher (12-wk-old) turkeys using 2 separate experiments. In each experiment, day-old poults were randomly allocated to 3 treatment groups, with 10 turkeys in each group (N = 30 turkeys/experiment). The treatment groups were a negative control (turkeys without PF supplementation or SH challenge), an SH control (SC; turkeys challenged with SH without PF supplementation), and a test group (PFS; turkeys supplemented with PF and challenged with SH). Supplementation of PF at 10¹² cfu/5 gallons water was provided to the turkeys in the PFS groups for 12 wk. The turkeys in the SC and PFS groups were challenged with SH at 10⁸ cfu/turkey at 11 wk of age. Five turkeys from each group were euthanized 2 and 7 d after SH challenge. The cecum, liver, and spleen samples were collected to determine colonization of SH in the cecum and SH dissemination to the targeted internal organs. Propionibacterium freudenreichii subsp. freudenreichii B3523 was recovered at 4.0 log₁₀ cfu/g in the turkey cecum. Supplementation of PF reduced the cecal colonization of SH by >2.0 log₁₀ cfu/g in finishing turkeys (P < 0.05). Similarly, PF supplementation reduced SH dissemination to the spleen (P < 0.05). Our investigations revealed that PF could be a biocontrol strategy to reduce Salmonella colonization and its spread to internal organs in turkeys.