Abstract: 【Objective】 This study aimed to investigate the effects of Dendrobium nobile polysaccharide on the cecal microbiota of Zhuxiang chickens,providing a theoretical basis for analyzing the mechanism of the polysaccharide-gut microbiota-host health interaction. 【Method】 Sixty 6-month-old Zhuxiang chickens were randomly divided into control (CK) and polysaccharide (DNP) groups,with 5 replicates per group (6 chickens each).Chickens in CK group were fed basal diet,while chickens in DNP group were fed a diet supplemented with 800 mg/kg Dendrobium nobile polysaccharides.After 60 days of feeding,one chicken per replicate had been selected,and their cecal contents were collected for 16S rRNA high-throughput sequencing.Alpha diversity,principal coordinate analysis (PCoA),taxonomic composition,differential species,and functional prediction analysis were performed. 【Result】 There was no significant difference of Alpha diversity index between DNP and CK groups (P＞0.05).PERMANOVA analysis results indicated that compared with control group,Dendrobium nobile polysaccharides treatment had a significant effect on the formation of the intestinal microbiota in Zhuxiang chickens (P＜0.05).In the gut microbiota of Zhuxiang chickens,there were six dominant phyla at the phylum level,such as Bacteroidota and Firmicutes,and 23 dominant genera at the genus level,such as Bacteroides and Rikenellaceae RC9_gut_group.Compared with control group,Dendrobium nobile polysaccharide treatment significantly increased the abundance of beneficial bacteria such as Christensenellaceae_R-7_group and UCG-005 in cecal microorganisms of Zhuxiang chickens (P＜0.05),and significantly decreased the abundance of potentially harmful bacteria such as Enterococcus and Campylobacter (P＜0.05).KEGG pathway annotation results showed that the cecal microbiota of Zhuxiang chickens were mainly enriched in metabolic pathways. 【Conclusion】 Dendrobium nobile polysaccharides could regulate the cecal microbiota structure of Zhuxiang chickens.By increasing the abundance of beneficial bacteria such as norank_o_Clostridia_vadinBB60_group and reducing the abundance of harmful bacteria such as Enterococcus,it could optimize the intestinal microecological balance and promote the healthy growth of Zhuxiang chickens.

Key words: Zhuxiang chickens; Dendrobium nobile polysaccharide; 16S rRNA; cecal microbiota