Seasonal dynamics, dietary patterns, and bamboo leaf nutrition shape the phyllosphere-associated gut microbiota of red pandas.

Background: The gut microbiota of bamboo-eating red pandas (Ailurus fulgens) comprises a intricate and multifaceted ecosystem influenced by numerous factors. Despite considerable research dedicated to captive red pandas, the microbial dynamics observed in wild populations are still not well understood. To address this research gap, our study employed advanced techniques such as high-throughput sequencing and metagenomic analysis to characterize the microbial communities and their functional profiles in fresh fecal samples from wild red pandas and in samples of their primary food source. Our objective was to conduct a thorough examination of how seasonality, diet, bamboo leaf nutrition, and phyllosphere-associated microorganisms affect the gut microbiota of red pandas.

Results: Our findings reveal that seasonal variations have a notable impact on the composition, structure, and functionalities of red pandas' gut microbiota. Specifically, autumn and winter exhibit heightened microbial diversity and richness. Moreover, during different feeding phases (leaf-feeding, shoot-feeding, and mixed-feeding), the gut microbiota displays varied cellulose-digesting abilities, marked by increased expression of key enzymes during high-fiber dietary phases. Our analysis reveals robust correlations between bamboo nutrients and microbial communities in both bamboo and red panda guts. Notably, bamboo's crude protein and phosphorus content are pivotal in shaping the phyllosphere and gut microbial communities, while crude fat, crude protein, and phosphorus emerge as key drivers of microbial structure. Seasonal fluctuations in microbial populations of both bamboo and red panda guts with shared genera, underscore their tight linkage and interconnected seasonal adaptations.

Conclusions: In conclusion, our study provides a comprehensive understanding of how seasonality, diet, and bamboo leaf nutrition shape the gut microbiota of red panda connected to bamboo microbiome. It underscores the gut microbes' indispensable role in facilitating red pandas' adaptation to their bamboo-based diet, crucial for their survival in natural habitats.