Bidirectional regulation of the brain-gut axis in

Although existing research has uncovered the association between psychological stress and gut microbiota dysbiosis, the causal relationship remains unclear. The direct impact of psychological stress on gut microbiota and the potential bidirectional mechanisms remain unclear, including the specific molecular pathways involved. This study investigates the impact of psychological stress on the gut microbiota and associated metabolites in wild Hainan macaques, revealing that stress significantly alters microbial composition and function. Specifically, stress-induced changes in the gut microbiota are linked to shifts in key metabolites, particularly coumarins, which are known to interact with the nervous system. This suggests a feedback loop where stress modulates neurological function via microbiota-derived metabolites. We identified several differential metabolites, including specific C10757, that can serve as biomarkers for detecting stress-induced health risks. These findings highlight the potential of microbiota-based interventions to mitigate stress-related health issues and provide essential data for wildlife health monitoring. The study highlights the role of gut microbiota as a stress biomarker, underscoring the importance of psychological well-being in wildlife conservation and research to guide ethical animal management. IMPORTANCE: This study uncovers how psychological stress alters gut microbiota in wild animals, enhancing understanding of the gut-brain axis in natural ecosystems. Crucially, it identifies microbial profiles as non-invasive stress biomarkers, enabling early detection of environmental threats in conservation. The findings emphasize the ethical need to incorporate stress assessments (e.g., microbiota and cortisol analyses) into wildlife research to ensure welfare and data validity. Mechanistic parallels with captive species suggest evolutionary conservation of gut-brain pathways, opening avenues for cross-species therapies. By bridging psychobiology and conservation, this work establishes a framework for stress resilience interventions and ethical wildlife management, advancing both ecological health and humane science. Future research should explore microbiota-targeted strategies and cross-species applicability to optimize conservation outcomes.