Hazardous potential evaluation of biochar exposure on mice through analyses of gut-microbiome and fatty acids in brain

In an effort to enhance crop yield and soil fertility, the use of biochar has been widely practiced in a sector of agricultural industry. The use of biochar has been also deemed a strategic measure to abate catastrophic consequences (triggered by global warming) considering its intrinsic carbon negativity. Also, biochar has been fed into livestock as supplement due to its beneficial biological effects (such as the fast growth rate). Nonetheless, biosafety in line with the use of biochar has not been discussed with a fully transparent manner. As such, it is of great importance to scrutinize a hazardous potential when biochar is fed into livestock. To this end, we fed mice with control chow, 0.6 wt%, and 1.2 wt% biochar mixed ones. In the controlled group, anxiety symptoms were observed in the elevated plus maze test and light and dark box test, and the despair-like behavior was identified in forced swim test. The behavioral changes caused by biochar were higher than ≥ 3 times. Also, the trends in the main composition of fatty acids in mouse brain were changed. Decrease in serotonin-related gene expression was resulted from the controlled group. TPH and SERT (that are serotonin-related genes) also decreased ≤ 55% only from the biochar group. Interestingly, the diversity of microorganisms (microbiome) of mouse gut was enhanced. It was concluded that biochar likely affects mouse mood-related behavior and the gut microbiome population. Therefore, this study revealed that the exposure of biochar into the living organisms could have a negative effect, thereby leading to the adverse effects on the ecosystem. Also, the comprehensive/systematic investigations on a hazardous potential of biochar should be administrated with the top priority in the near future.