Wild Japanese macaques (Macaca fuscata Blyth) living in the highland and lowland areas of Yakushima are known to have different diets, with highland individuals consuming more leaves. We aim to clarify whether and how these differences in diet are also reflected by gut microbial composition and fermentation ability. Therefore, we conduct an in vitro fermentation assay using fresh feces from macaques as inoculum and dry leaf powder of Eurya japonica Thunb. as a substrate. Fermentation activity was higher for feces collected in the highland, as evidenced by higher gas and butyric acid production and lower pH. Genetic analysis indicated separation of highland and lowland in terms of both community structure and function of the gut microbiota. Comparison of feces and suspension after fermentation indicated that the community structure changed during fermentation, and the change was larger for lowland samples. Analysis of the 16S rRNA V3-V4 barcoding region of the gut microbiota showed that community structure was clearly clustered between the two areas. Furthermore, metagenomic analysis indicated separation by gene and pathway abundance patterns. Two pathways (glycogen biosynthesis I and D-galacturonate degradation I) were enriched in lowland samples, possibly related to the fruit-eating lifestyle in the lowland. Overall, we demonstrated that the more leaf-eating highland Japanese macaques harbor gut microbiota with higher leaf fermentation ability compared with the more fruit-eating lowland ones. Broad, non-specific taxonomic and functional gut microbiome differences suggest that this pattern may be driven by a complex interplay between many taxa and pathways rather than single functional traits.

中文翻译：

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高原和低地屋久岛野生日本猕猴肠道菌群的发酵能力：体外发酵测定和遗传分析。

居住在屋久岛高地和低地地区的野生日本猕猴（Macaca fuscata Blyth）具有不同的饮食习惯，高地人食用更多的叶子。我们的目的是弄清肠道微生物组成和发酵能力是否以及如何通过饮食来反映这些饮食差异。因此，我们使用来自猕猴的新鲜粪便作为接种物和欧亚粳稻的干叶粉进行体外发酵测定。作为基材。高地收集的粪便的发酵活性更高，这可通过较高的气体和丁酸产量和较低的pH值来证明。遗传分析表明，在肠道菌群的群落结构和功能上，高地和低地是分开的。发酵后粪便和悬浮液的比较表明，发酵过程中群落结构发生了变化，低地样品的变化较大。肠道菌群的16S rRNA V3-V4条形码区域的分析表明，群落结构明显聚集在两个区域之间。此外，宏基因组分析表明按基因和途径丰度模式进行分离。低地样品中富集了两条途径（糖原生物合成I和D-半乳糖醛酸降解I），这可能与低地的水果饮食生活方式有关。总的来说，我们证明与高果饮食的低地猕猴相比，高叶饮食的高地猕猴具有较高的叶片发酵能力，其肠道菌群较高。广阔，