library_construction_protocol: Fresh feces from each mouse were collected and temporarily placed in sterile tubules, and then snap-frozen in liquid nitrogen.Total DNA from stool bacteria was extracted using QIAamp DNA stool mini kit from Qiagen (Germantown, MD, USA) according to the manufacturer's instructions. Then, the target fragment was selected for PCR amplification, and the magnetic beads were purified, recycled and quantified by fluorescence. Illumina TruSeq Nano DNA LT Library Prep Kit was used  for the construction of sequencing libraries. RNA libraries were prepared for sequencing using standard Illumina protocols