LAUSR

The influence of gut microbiota on brain function and brain disorders has been attracted more and more attention. Trimethylamine N-oxide (TMAO), an indirect metabolite of gut microbiota, has been linked to aging, cognitive impairment, and other brain disorders. However, the relationship between TMAO and social behaviors are still poorly understood. Adult male mice were exposed to drinking water containing 3,3- Dimethyl-1-butanol (DMB), an indirect inhibitors of TMAO, for 21 continuous days followed by a series of behavioral tests to detect the effect of DMB exposure on social behaviors, mainly including social dominance test (SDT), bedding preference test (BP), sexual preference test (SP), social interaction test (SI), open field test (OFT), tail suspension test (TST), forced swim test (FST), novelty suppressed feeding test (NSF), and novel object recognition (NOR) task. In the SDT, compared with the control group, the mice treated with DMB (both 0.2% and 1.0%), both high-ranked and low-ranked mice, showed a reduction in the number of victories. There is no statistical difference on sexual preference, anxiety, depression-like behavior phenotype, and memory formation. In conclusion, the present findings provide direct evidence, for the first time, that repeated DMB exposure produces significant effects on social dominance of adult mice, without any effects on sexual preference, anxiety, depression-like behavior phenotype or memory formation, highlighting the regulatory effects of gut-brain interaction on social behaviors.