Bacteroides uniformis CECT 7771 Modulates the Brain Reward Response to Reduce Binge Eating and Anxiety-Like Behavior in Rat

Food addiction (FA) is characterized by behavioral and neurochemical changes linked to loss of food intake control. Gut microbiota may influence appetite and food intake via endocrine and neural routes. The gut microbiota is known to impact homeostatic energy mechanisms, but its role in regulating the reward system is less certain. We show that the administration of Bacteroides uniformis CECT 7771 (B. uniformis) in a rat FA model impacts on the brain reward response, ameliorating binge eating and decreasing anxiety-like behavior. These effects are mediated, at least in part, by changes in the levels of dopamine, serotonin, and noradrenaline in the nucleus accumbens and in the expression of dopamine D1 and D2 receptors in the prefrontal cortex and intestine. B. uniformis reverses the fasting-induced microbiota changes and increases the abundance of species linked to healthy metabolotypes. Our data indicate that microbiota-based interventions might help to control compulsive overeating by modulating the reward response.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by grants AGL2014-52101-P and AGL2017-88801-P from the Ministry of Science, Innovation and Universities (MCIU, Spain) and by grant PROMETEO/2019/015 from “Conselleria de Educación, Investigación, Cultura y Deporte” (Generalitat Valenciana, Spain). The contracts of ABP are also supported by grant AGL2017-88801-P. The pre-doctoral contract (FPI) of ILA and the technician contract (PTA) of IC from MCIU (Spain) are also fully acknowledged.Peer reviewe