Effect of supplementation of a dairy-originated probiotic bacterium, Propionibacterium freudenreichii subsp. freudenreichii, on the cecal microbiome of turkeys challenged with multidrug-resistant Salmonella Heidelberg1

Abstract

A dairy-originated probiotic bacterium, Propionibacterium freudenreichii subsp. freudenreichii B3523 (PF) was found to be effective in reducing multidrug-resistant Salmonella Heidelberg (MDR SH) colonization in turkey poults (2-week-old) and growing (7-week-old) and finishing (12-week-old) turkeys. In this study, we explored the potential for microbiome modulation in the cecum of turkeys of different age groups due to PF supplementation in conjunction with MDR SH challenge. One-day-old commercial turkey poults were allocated to 3 treatment groups: negative control (N; turkeys without PF supplementation or SH challenge), SH control (S; turkeys challenged with SH without PF supplementation), and test group (P; turkeys supplemented with PF and challenged with SH). Turkeys were supplemented with 1010 CFU PF in 5-gallon (18.9 L) water until 7 or 12 week of age. At the 6th or 11th wk, turkeys were challenged with SH at 106 and 108 CFU/bird by crop gavage, respectively. After 2 and 7 d of challenge (2-d postinoculation [PI] and 7-d PI, respectively), cecal samples were collected and microbiome analysis was conducted using Illumina MiSeq. The experiments were repeated twice with 8 and 10 turkeys/group for 7- and 12-wk studies, respectively. Results indicated that the species richness and abundance (Shannon diversity index) was similar among the treatment groups. However, treatments caused apparent clustering of the samples among each other (P < 0.05). Firmicutes was the predominant phylum in the growing and finishing turkey cecum which was evenly distributed among the treatments except on wk 12 where the relative abundance of Firmicutes was significantly higher in P than in N (P = 0.02). The MDR SH challenge resulted in modulation of microflora such as Streptococcus, Gordonibacter, and Turicibacter (P < 0.05) in the S groups compared with the P and N groups, known to be associated with inflammatory responses in birds and mammals. The supplementation of PF increased the relative abundance of carbohydrate-fermenting and short-chain fatty acid-producing genera in the P group compared with the S group (P < 0.05). Moreover, the results revealed that PF supplementation potentially modulated the beneficial microbiota in the P group, which could mitigate SH carriage in turkeys.

Keywords: Propionibacterium; Salmonella Heidelberg; alternatives; dairy probiotic; microbiome.