Comparative analysis of fecal microbial community diversity between Bactrian camels and Mongolian cattle based on 16S rRNA gene sequencing

Xueqin Ma, Wenyi Ren, Shuangming Yang, Miao Liu, Weihao Kong, Xiaofeng Xu, Lili Zhang

Introduction The Alxa region is a typical arid and semi-arid ecosystem in northwestern China, where Bactrian camels and Mongolian cattle coexist under natural grazing conditions but differ markedly in feeding behavior and environmental tolerance. These differences may be reflected in host-associated gut microbial communities. This study compared the fecal microbiota of the two species to clarify microbial features associated with adaptation to the local desert grassland environment. Methods Fecal samples were collected from 12 healthy adult Bactrian camels and 12 healthy adult Mongolian cattle grazing on spring pasture in the Alxa region. Total microbial DNA was extracted from fecal samples, and the hypervariable region of the bacterial 16S rRNA gene was amplified and sequenced using the Illumina platform. Community composition, alpha and beta diversity, differential taxa and microbial co-occurrence networks were then analyzed. Results The Shannon index was significantly higher in Bactrian camels than in Mongolian cattle ( P = 0.049), whereas the Simpson index showed an opppsite trend ( P = 0.013). PCoA and NMDS analyses further showed significant separation between the fecal microbial communities of the two host species ( P = 0.001). At the phylum level, Bacillota and Bacteroidota dominated fecal samples from both species. At the genus level, the dominant taxa in Bactrian camels included Rikenellaceae_RC9_gut_group, norank_f_UCG-010, Christensenellaceae_R-7_group, UCG-005, Treponema and Bacteroides , whereas Mongolian cattle were dominated mainly by UCG-005, Rikenellaceae_RC9_gut_group and norank_f_UCG-010 . Co-occurrence network analysis showed that the camel microbial network had higher edge number, graph density and average degree, but lower network diameter, clustering coefficient and modularity, than the cattle network. The core nodes were UCG-005, Rikenellaceae_RC9_gut_group and Succinivibrio in Bactrian camels, and Rikenellaceae_RC9_gut_group, Bacteroides RF16 group and Prevotella in Mongolian cattle. Discussion These findings provide preliminary microbial evidence that Bactrian camels and Mongolian cattle maintain their survival by shaping distinct gut microbial community structures and functional interaction patterns.