Gut microbiota-derived gamma-aminobutyric acid improves host appetite by inhibiting satiety hormone secretion

Globally, appetite disorders have become an increasingly prominent public health issue. While short-term appetite loss may seem relatively harmless, prolonged instances can lead to serious physical and mental damage. In recent years, numerous studies have highlighted the significant role of the "microbiota-gut-brain" axis in the regulation of feeding behavior in organisms, suggesting that targeting the gut microbiota may be a novel therapeutic strategy for appetite disorders. However, the molecular mechanisms through which the gut microbiota mediates the increase in host appetite and the causal relationship between the two remain unclear. Based on this, we conducted 16S rRNA sequencing to analyze the gut microbiota of rabbits with high and low feed intake, followed by fecal microbiota transplantation (FMT) and metabolite gavage experiments to elucidate the underlying mechanisms. Our research indicates that the high feed intake group exhibited significant enrichment of the g__Bacteroides and gamma-aminobutyric acid (GABA), and intragastric administration of GABA effectively promoted the host's feeding behavior. The underlying mechanism involves GABA derived from the gut microbiota inhibiting the secretion of satiety hormones to enhance the host's feeding behavior. Furthermore, the results of FMT suggest that differences in gut microbiota composition may be a contributing factor to varying levels of feed intake in the host. In conclusion, these findings emphasize the role of the gut microbiota-derived GABA, in increasing host feed intake, offering a new target for the treatment of appetite disorders from the perspective of gut microbiota.IMPORTANCEThe incidence of anorexia is rapidly increasing and has become a global burden. Gut microbiota can participate in the regulation of host feeding behavior, yet the molecular mechanisms through which the gut microbiota mediates the increase in host appetite and the causal relationship between them remain unclear. In this study, we utilized 16S rRNA sequencing to investigate the composition of the gut microbiota in rabbits with varying levels of feed intake and employed fecal microbiota transplantation and gastric infusion experiments with gamma-aminobutyric acid (GABA) to elucidate the potential mechanisms involved. GABA derived from the gut microbiota can effectively enhance the host's feeding behavior by inhibiting the secretion of satiety hormones. This discovery underscores the pivotal role of the gut microbiota in modulating host appetite, offering novel research avenues and therapeutic targets for appetite disorders.