Analysis of Gut Microbial Communities and Functions in Passer ammodendri Under Two Extreme Environments

The gut microbiome regulates multiple physiological processes of the host and plays a significant role in the adaptation of wild animal hosts to extreme environments. The saxaul sparrow (Passer ammodendri) is a typical bird species found in the northwest of China, characterized by its strong adaptability to extreme environments. Studying it can help reveal the microbial adaptation mechanisms of the host to extreme environments. Therefore, we conducted a comparative analysis of the intestinal microbial community characteristics and functions of the saxaul sparrow in high-altitude (Pamir Plateau) and desert (Tazhong Town) habitats in Xinjiang. The results of full-length 16S rRNA sequencing and species annotation indicated that the bacterial species composition (relative abundance > 0.1%) of the intestinal microbiota community of the saxaul sparrow was Candidatus Arthromitus sp. SFB rat Yit, Escherichia coli, Enterococcus faecium, Enterococcus faecalis, and Klebsiella pneumoniae, in sequence. In addition, Lysinibacillus sphaericus is a unique strain specific to the Tazhong group, while Stenotrophomonas maltophilia has a much higher abundance in the Tazhong group than in the Pamir Plateau group. It is worth noting that both groups of samples contain potential opportunistic pathogenic bacteria, such as Escherichia coli and Klebsiella pneumoniae. The Shannon index of the Pamir Plateau group was lower than that of the Tazhong Town group (p = 0.0026), indicating that the intestinal microbial diversity of the Pamir Plateau group was lower than that of the Tazhong Town group. However, there was no significant difference in the ACE index between the two groups and it was not statistically significant (p > 0.05). The Beta diversity analysis revealed that the distance between the two groups of samples was considerable (p = 0.001), indicating a significant separation. The functional annotation results indicated that the Pamir Plateau group exhibited enhanced capabilities in carbohydrate metabolism, energy metabolism, and DNA damage repair, while the Tazhong Town group demonstrated enhanced lipid metabolism and detoxification abilities. These findings will help reveal the possible impact of the living environment on the composition and function of the intestinal microbiota of the saxaul sparrow, fill the gap in comparative studies of the intestinal microbiota characteristics of the saxaul sparrow in two extreme environments, and provide new theoretical support for subsequent related research.