Abstract:

Background & Aim: Overwintering is an important stage in the life history and evolution of animals in temperate and cold regions of the world, and successful overwintering is crucial for the reproduction and maintenance of animal populations. Gut microbiota and hosts have co-evolved and formed complex symbiotic relationships that play important roles in animal growth and development, health regulation and adaptation to harsh environments. Overwintering animals undergo not only adaptive changes in morphology, physiology and behavior, but also changes in their gut microbiota, which are essential for host adaptation to low temperatures. In recent years, the work on the gut microbiota of overwintering animals has received increasing attention.

Review results: (1) We summarized the current progress in studies of the gut microbiota of overwintering animals. The number of publications in this field has increased rapidly in recent years, and gut microbiota of hibernating animals has been studied most intensively. Gut microbial diversity, influencing factors, community assembly, and the mechanism of gut microbiota on overwintering animals are the research hotspots. (2) We analyzed the changes in diversity, composition and functional genes of the gut microbial community in overwintering animals. Bacteroidetes, Firmicutes and Proteobacteria dominate the gut bacterial communities in winter, and their diversity is lower than that in summer. The functional genes of the gut bacterial community in hibernating animals are mainly related to lipid metabolism. (3) We summarized the main factors influencing the gut microbial community of overwintering animals. The gut microbial community is closely related to the gut morphology and physiology, species identification, diet, overwintering strategy, spatio-temporal and climatic changes. (4) We discussed the important functions of the gut microbiota during overwintering. Gut microbiota are involved in nutrition acquisition and energy metabolism, heat production, and influenced host cold tolerance and immunity of the hosts.

Suggestions & Perspectives: This review can enhance our understanding of the maintenance of gut microbial diversity and its ecological function in the non-growing season, and help to understand the potential impact of gut microbiota and their host interaction mechanisms on the regulation of animal adaptation to environmental changes.

Key words: Hibernation, Diapause, Gut microbiota, Host-microbe interaction, Winter biodiversity, Cold adaptation