Abstract: 【Objective】 The purpose of this study was to compare the diversity,species and relative abundance of microbial community in different intestinal segments of meat ducks by metagenome sequencing,species annotation and functional annotation,so as to explore the spatial heterogeneity of gut microbiota in meat ducks.【Method】 The contents of duodenum,jejunum,ileum and cecum were collected from 6-week-old Beijing ducks and Liancheng White ducks raised in the same environment in turn,and the species and relative abundance of gut microbiota were obtained by metagenome sequencing.Based on the microbial abundance table,wilcoxon rank sum test was used to compare the differences of dominant microorganisms,microbial species,microbial relative abundance,microbial community diversity and microbial functional diversity in different intestinal segments,and t test was used to screen the significantly different bacterial genera in different intestinal segments of Pekin ducks and Liancheng White ducks.【Result】 45 phyla,84 classes,186 orders,418 families,1 400 genera and 3 467 species were identified in this experiment.The dominant phyla of the four intestinal segments were Firmacutes,Bacteroides,Proteobacteria and Actinomycetes,and the distribution of the four phyla in different intestinal segments was different.Bacteroides and Phocaeicola were the dominant genera in the four intestinal segments,and the species and abundance of the dominant genera were different among the groups of different intestinal segments.From duodenum to cecum,the composition,relative abundance and community diversity of microbiota changed significantly (P＜0.05),and the microbial composition of duodenum,jejunum and ileum was highly similar and obviously separated from cecum microbiota.At the same time,the community diversity of cecum microbiota was also significantly higher than that of other intestinal segments (P＜0.01).Compared with duodenum,jejunum and ileum,the metabolic pathways such as bacterial chemotaxis,amino sugar,nucleotide sugar metabolizing fatty acid biosynthesis of cecum microbiota were up-regulated,and 31 different bacteria genera of Beijing ducks and Liancheng White ducks were enriched in cecum,which were higher than that of duodenum,jejunum and ileum.【Conclusion】 The quantity,relative abundance and community diversity of microbiota in cecum of meat ducks were higher than those in duodenum,jejunum and ileum,which provided theoretical basis for analyzing the regulation mechanism of gut microbiota in meat ducks,accurately regulating energy metabolism level and immune function of meat ducks,and provided reference for further study of gut microbiota in meat ducks.

Key words: duck; gut microbiota; metagenome; spatial heterogeneity