Abstract: 【Objective】 This experiment was aimed to analyze the differences in microbial colonization patterns on the back,neck and rectal chyme of Dezhou male donkeys. 【Method】 A total of 3 000 Dezhou male donkeys with uniform skin thickness were fed with the same basal diet.The skin thickness on the back and neck of donkeys was continuously monitored.Seven donkeys with high and low skin thickness increments in both areas were selected,respectively.The composition and function of microbial communities on the back and neck surfaces,as well as in the rectal chyme,were analyzed by determining the sequences of 16S rRNA amplification. 【Result】 There were significant differences in the thickness increment of donkey skin between the high and low groups (P＜0.05).There was no significant difference of microbiota in Alpha diversity of skin on the back,neck and rectal chyme between the two groups (P＞0.05).However,the results of principal co-ordinates analysis (PCoA) showed that there were varying degrees of differences in microbial community clustering between the two groups (P＜0.05).Venn diagram revealed that there was common amplicon sequence variant (ASV) or unique ASV of microbiota in skin on the back,neck and rectal chyme between the two groups.At the phylum level,the dominant bacteria in different parts of the two groups included Firmicutes,Actinobacteriota,Chloroflexi,Proteobacteria,Bacteroidota,etc.At the genus level,the dominant bacteria included Clostridium_sensu_stricto_1,Corynebacterium,Streptococcus,Ornithinimicrobium,etc.Among these,Streptococcus was the dominant bacteria in the rectal chyme microbiota,and Ornithinimicrobium was the dominant bacteria in skin on the back and neck.Differential species analysis results showed that compared with the neck skin of low thickness increment group,23 genera were enriched in the neck skin of high thickness increment group.Compared with the back skin of low thickness increment group,7 genera were enriched in the back skin of high group.Compared with the rectal chyme of low thickness increment group,13 genera were enriched in the rectal chyme of high thickness increment group. 【Conclusion】 Dezhou donkeys with varying skin thickness had different microbial community structures and functions.Moreover,compared with rectal chyme,the microbial diversity of skin showed a higher trend.The results provided a theoretical basis for analyzing the microbial colonization pattern and potential regulatory mechanisms of donkey skin transformation efficiency in Dezhou donkeys.

Key words: Dezhou donkeys; intestinal microbiota; skin microbiota; donkey skin thickness; colonization pattern