Fig. 7

Graphic summary of the main findings. On the basis of the “Lunar Palace 365” experiment and species analysis of metagenomics, we identified four potential psychobiology (Bacteroides uniformis, Roseburia inulinivorans, Eubacterium rectale, and Faecalibacterium prausnitzii). Furthermore, on the basis of the multiomics analysis, we determined the functional mechanism of these potential psychobiotics on mood was three pathways related to nervous system functions: first, by fermenting dietary fibers, they may produce short-chain fatty acids such as butyric acid and propionic acid; second, they may regulate amino acid metabolism pathways of aspartic acid, glutamic acid and tryptophan, etc. (e.g., converting glutamic acid to gamma–aminobutyric acid (GABA); converting tryptophan to serotonin, kynurenic acid, or tryptamine); and third, they may regulate other pathways such as taurine metabolism and cortisol metabolism. Furthermore, we verified the effect and mechanism of these potential psychobiotics on mood through animal experiments. The results showed that these potential psychobiotics reduced the CUMS-induced depression- and anxiety-like behavior in rats. Most of the functional mechanisms of these potential psychobiotics on mood found in the “Lunar Palace 365” experiment based on multiomics analysis have been verified in animal experiments. Interestingly, we also found other mechanisms of these potential psychobiotics to improve mood, such as producing other small molecule metabolites (e.g., histamine, L-glutamine and noradrenaline hydrochloride), and reduce the increase in intestinal permeability and inflammatory response caused by CUMS. This improves mood by affecting the enteric nervous system (ENS) and central nervous system (CNS)