The 16S rRNA gene segments spanning the variable V5 and V6 regions were amplified from DNA from mucus, contents, or mouse faecal samples using a multiplex approach with barcoded primers. The PCR amplified 16S V5-V6 amplicons were purified and prepared for sequencing on the Ion torrent PGM system according to the manufacturer’s instructions (Life Technologies). The FASTQ files provided correspond to the two microbial diversity status tested in the study: SPF (2 files) and sDMDMm2 defined flora (1 file). Each file corresponds to an Ion torrent chip.The corresponding mapping files (containing barcodes and sample metadata) are also provided in TXT format. These files can be used directly for analysis (eg. using the Qiime pipeline).