Intermittent fasting driven different adaptive strategies in Eothenomys miletus (Red-backed vole) at different altitudes: based on the patterns of variations in intestinal microbiota.

In the face of global warming, the Eothenomys miletus (Red - backed vole), a species dwelling in highland mountainous regions, is likely to encounter difficulties. Given its restricted mobility, it may struggle with the uncertainty of food resources. In such circumstances, it becomes increasingly crucial for this species to adjust its diverse responses to fulfill its energy requirements. E. miletus specimens were gathered from different altitudes for intermittent fasting (IF) experiments. In these experiments, the specimens underwent random fasting for 3 days within a seven - day cycle. 16 S rDNA sequencing technology, combined with physiological and biochemical assessment methods, was employed to analyze the impacts of IF on gut microorganisms, physiological and biochemical indicators, and the interactions among them. By exploring the adaptive responses of E. miletus to uncertain food resources, which provides novel perspectives on the adaptive strategies of small rodents in the wild during food-scarce periods. The results showed that IF significantly reduced the body mass of E. miletus. Significant correlations were found between various gut microbes and physiological indicators. Under IF conditions, E. miletus at high altitudes experienced a smaller reduction in body mass compared to those at low altitudes. Moreover, the diversity of gut microbes and endemic bacteria in E. miletus at high altitudes varied more than that of low altitudes. The differential response in body mass reduction between high-altitude and low-altitude E. miletus under IF conditions indicated that altitude is an important factor influencing the physiological adaptation of this species to dietary changes. High-altitude E. miletus showed a relatively smaller decrease in body mass, potentially reflecting their better adaptation to environmental stressors over time. Additionally, the greater variation in gut microbe diversity and endemic bacteria in high-altitude E. miletus implied that altitude may shape the gut microbiota, which in turn could be related to their unique physiological adaptations at high altitudes. Overall, E. miletus at high altitude may possess more stable regulatory mechanisms, demonstrating better adaptation under IF conditions. These findings provide valuable insights into the complex interplay between diet, altitude, and gut microbiota in the context of E. miletus physiology, highlighting the importance of considering both environmental and microbial factors in understanding the species' responses to nutritional challenges.​.