Abstract:Objective To analyze the structure and composition of the tree shrew hindgut microbiota by Illumina PE250 sequencing technology. Methods Three male 10?month?old tree shrews were selected. The V3 - V4 region was amplified with universal primers of bacteria 16SrDNA and sequenced with the Illumina PE250 platform after the extraction of total DNA. Results A total of 160 157 valid sequences and 437 operational taxonomic units (OTUs) were obtained. The bacteria in the tree shrew hindgut are from 9 phyla, 19 classes, 37 orders, 68 families, 137 genera, and 194 species. Among them, (i) Firmicutes and Proteobacteria had the highest abundance, at 63. 30% and 28. 52%, respectively. (ii) The dominant classes were Bacilli and Gammaproteobacteria ( 51. 46%, 28. 02%). ( iii ) The abundances of Lactobacillales and Enterobacteriales were high, at 45. 33% and 27. 51%. (iv) Dominant families were Lactobacillaceae (35. 30%) and Enterobacteriaceae (27. 51%). (v) Lactobacillus and Escherichia?Shigella were the dominant genera (35. 30%, 27. 49%). (vi) At the species level, the abundance of cultured bacteria was 37. 10%, that of unclassified bacteria was 27. 69%, and that of uncultured bacteria was 35. 21%. Lactobacillus salivarius was the most abundant species (26. 66%) among the cultured bacteria. Of the 20 species with the highest abundance, eight (40%) were unclassified and new species. Some differences among individuals in terms of bacterial communities were identified. Conclusions The tree shrew hindgut microbiota has rich diversity, and there are many bacteria that have not been identified and have relatively high abundance, which needs further study.