The results showed that after DMB supplementation, the TMAO levels in the serum of mice in the ABX + DMB + FMT-APP/PS1 and ABX + DMB + FMT-AD groups were significantly decreased compared to those in the ABX + FMT-APP/PS1 and ABX + FMT-AD groups, respectively (ABX + FMT-APP/PS1 vs. ABX + DMB + FMT-APP/PS1, P < 0.0001; ABX + FMT-AD vs. ABX + DMB + FMT-AD, P = 0.0029) (Figure 4B). The gene discussed is APP; the disease is Alzheimer disease.