Feed presentation options in Swine early fattening mitigates Salmonella shedding and specifically modulates the faecal microbiota.

AIMS: The object of this study was to determine the impact of only modifying the processing and/or particle size of pig feed on Salmonella shedding and faecal microbiota.

METHODS AND RESULTS: Pigs were fed a diet that varied only by their processing (pellet or mash) and their particle size (500, 750 or 1250 μm) for 21 days. Salmonella detection in faeces and seroconversion were determined. Faecal microbiota was assessed by Ion Torrent amplicon sequencing and real-time PCR. Significantly fewer pigs (P < 0·05) shed Salmonella in the groups fed mash 500 (1) and mash or pellet 1250 (5 each) compared to the commercial reference group (15) fed pellet 500. Both mash processing and large particle size raised the proportion and number of bacteria from the Bifidobacterium genus in the faecal microbiota of the pigs. Thirteen other taxa significantly varied (P < 0·0005) with feed presentation.

CONCLUSION: Mash processing and/or large particle size in pig feed reduces Salmonella shedding prevalence and promotes beneficial populations of digestive microbiota.

SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to demonstrate a difference in Salmonella shedding through only modifying pig feed presentation and is the first to extensively describe modifications of faecal microbiota.