INTRODUCTION
The gut provides a rich and favorable ecological environment for
microbial communities, facilitating a complex and dynamic equilibrium
among microorganisms. This balance is subject to continuous
modifications across different hosts or developmental stages,
contributing to a variety of physiological (Hertli & Zimmermann,
2022 ) and pathological processes, including metabolism (Lindsay,
Metcalfe & Llewellyn, 2020; Wei et al., 2023 ), nutrient absorption
(Flint et al., 2012 ), immune regulation (Siddiqui, Maciver
& Khan, 2022; Wei et al., 2023 ), and host ecological behavior
(O’Donnell et al., 2020 ). The composition and structure of normal
gut microbiota serve as indicators for assessing animal health as well
as diagnosing or preventing disease (Hu et al., 2017; Kundu et
al., 2017; Rosshart et al., 2017 ). Gut microbes are shaped by a
multitude of factors, such as the evolutionary status (Kartzinel
et al., 2019 ), feeding habits (Jiang et al., 2017 ), distribution
(Qin et al., 2014 ), seasonal variation (Sun et al., 2016;
Gao, Yang & Shi, 2023 ), and climate (Greenspan et al., 2020; Li
et al., 2020 ). However, the primary determinants affecting the
composition of the gut microbiota are the genetic background and dietary
habits of the host (Kovacs et al., 2011; Doré & Blottière,
2015 ). Understanding these factors is crucial for studying the ecology
and evolution of animal gut microbes.
A variety of factors, including sex, geographical population, breeding
status, health condition, local altitude, and temperature, influence the
composition and characteristics of gut microbes. For example,
significant sex-based differences in microbial community structure have
been reported in wild Calotes versicolor , with theBacteroide and Ochrobactrum genera found to be dominant in
wild females and males, respectively (Zhang et al., 2022 ).
Differences in fecal microbial abundance and gene functional types have
also been noted between the Guilin and Xiangyang populations ofPtyas dhumnades (Li, Sun & Xu, 2021 ). Additionally, the
relative abundance of Shigella species in fecal samples ofElaphe carinata , noted for its lack of intestinal diseases, is
considerably higher than that of two congeneric species, suggesting a
potential link to intestinal health (Lu et al., 2019 ). Research
has also shown that conditional or potentially pathogenic bacteria are
often present in the animal gut microbiota. For example, potential
pathogenic bacteria such as Citrobacter , Trichococcus , andErysipelothrix have been detected in the intestines of wildRhabdophis tigrinus (Tang et al., 2019 ) andRhabdophis subminiatu s (Tang et al., 2019 ). Significant
differences have also been found in the composition of gut microbiota
among populations of Phrynocephalus vlangalii living at different
altitudes, with changes corresponding to the altitudinal gradient
(Zhang et al., 2018 ). Furthermore, based on semi-natural
experiments, Bestion et al . (2017 ) demonstrated
that increasing temperature can lead to a decrease in microbial
diversity in wild lizards, potentially negatively impacting host
survival. Conversely, gut microbiota can be regulated to enhance immune
capacity in lizards, thus facilitating adaptation to climate change
(Yang et al., 2024 ).
The bamboo pitviper (Viridovipera stejnegeri ) is a common
venomous snake with wide distribution across China and Vietnam
(David et al., 2001; 2002; Guo et al., 2022 ). It typically
inhabits the rocks of streams, grassy and bushy areas, roadsides,
vegetable fields, and rock crevices in mountainous areas at elevations
ranging from 150 to 2 200 m. These snakes primarily feed on mice,
frogs, lizards, and birds (Zhao, 1998; Guo et al., 2022 ).
Research by Guo et al . (2016 ) on mitochondrial gene
fragments and nuclear genes revealed significant population
differentiation within this species.
Snakes, lacking the ability to chew, possess a robust intestinal
digestion capacity and remarkably strong hunger tolerance. In the
current study, we analyzed the composition, abundance, and
carbohydrate-active enzymes (CAZymes) of gut microbes in different
populations of V. stejnegeri using metagenomic next-generation
sequencing. Our main goal was to compare the gut microbiota in the three
different populations and investigate the potential relationship between
habitat factors and gut microbes as well as the crucial roles played by
gut microbes during carbohydrate metabolism within populations ofV. stejnegeri .