Study On The Microbial-gut-brain Axis Mechanism Of Tannin Regulating Spatial Memory And Food Storage Behavior In Mic

The rodent-plant seed is a major component of forest ecosystems and plays a key role in the maintenance of biodiversity and ecosystem function.Plant seeds are rich in nutrients and can provide food for rodents,as well as attracting rodents to spread,disperse seed stores and promote the spread of plant propagules,seedling establishment and population renewal.Reciprocal relationships between rodents and plant seeds are often regulated by the physicochemical properties of the seeds,for example seed tannins are important secondary metabolites that influence the dispersal feeding behaviour of rodents.However,the important effects of tannins as secondary metabolites on the nutritional metabolism and the function of the intestinal microflora in storage of rodents,as well as the pathways and physiological mechanisms by which tannins regulate rodent food storage preferences,have not been specifically investigated to date.Crucially,no study has yet elucidated the effects of seed tannins on storage of rodent behaviour along the multidimensional plant secondary metabolite-rodent gut microbial-brain-spatial cognition dimensions.Thus,the mechanism by which tannins regulate the microbial-gut-brain axis that co-evolves with seeds in storage of rodents is unclear.This study focuses on the scientific question of how seed tannins regulate spatial memory and thus influence storage behaviour in rodents.The study investigates the response of seed tannins to the composition and metabolic characteristics of the gut microbiota of rodents and their regulation of spatial memory from the unique perspective of plant-animal-microbial interactions,and elucidates the molecular mechanism of the microbial-gut-brain axis of tannin regulation of spatial memory in rodents.This will reveal the effects of seed tannins and gut microbiota interactions on the spatial memory and storage strategies of food-storing rodents and their regulatory mechanisms.To elucidate the reciprocal relationship between rodents and plant seeds in a multidimensional manner in seed tannin-gut microbiota-brain-spatial memory-storage behaviour.It provides new ideas for the study of gut microbial regulation of reciprocal relationships between plants and animals,and is important for revealing the synergistic evolution among plants,animals and microorganisms.In this study,chipmunks were treated with cork oak and tannin water,and C57BL/6J mice were subjected to fecal transplantation.Using 16 S r RNA gut microbiota analysis,faecal transplantation and metabolomic analysis to study the effects of seed tannins on the gut microbiota and their mediated metabolites in chipmunks,and maze and enclosure experiments to study changes in spatial memory and hoarding behaviour in chipmunks,the aim was to investigate the mechanisms underlying the regulation of spatial memory and hoarding behaviour in food-storing rodents by plant secondary metabolites(tannins)via the microbial-gut-brain axis.The main experimental results are as follows:⑴Analysis by 16 S r RNA sequencing revealed that neither cork oak nor tannin water altered the α diversity of the chipmunks,but both different treatment groups significantly altered the β diversity,suggesting that tannins in cork oak can alter the structure of the chipmunk gut microbiota.⑵ The eight-arm maze experiment demonstrated that the number of working memory errors in the maze was significantly lower in the cork oak treatment and tannin treatment groups than in the cork oak control and tannin control groups,while the number of reference memory errors in the maze in the cork oak treatment and tannin treatment groups was not significant in relation to the cork oak control and tannin control groups,indicating that both feeding cork oak and drinking tannin water improved the spatial memory of chipmunks and significantly increased their access to the number of times in the correct arm.⑶The results of the semi-natural enclosure showed that the proportion of seeds remaining in situ was significantly higher in the cork oak control group than in the cork oak treatment group,while the proportion of seeds in scatter hoarding was significantly higher in the cork oak treatment group than in the cork oak control group,suggesting that cork oak can improve the hoarding behaviour of chipmunks.⑷Fecal transplantation did not significantly alter the α diversity of the mouse gut microbiota,but significantly altered the β diversity of the mouse gut microbiota⑸The Barnes maze showed that the cork oak treatment transplant group and the tannin treatment transplant group were significantly better than the cork oak control group and the tannin control transplant group in terms of time and distance to find the target hole,indicating that the transplanted gut microbiota colonised the mice’s intestines and significantly improved their spatial memory ability,further suggesting that the tannins in cork oak are improving the spatial memory ability of the chipmunk through the gut microbiota.⑹The serum metabolome showed that acorn tannin improved the cognition and spatial memory of chipmunks by elevating tryptophan levels and promoting the 5-hydroxytryptamine;the fatty acid metabolome showed that acorn tannin increased isovaleric acid levels and improved the cognition of chipmunks;the combined multiomics analysis showed strong correlations between multiple gut microbiota and metabolites,suggesting that acorn tannin modulates multiple metabolites to improve the spatial memory and ultimately the storage behaviour of chipmunks by altering the composition of the gut microbiota.