In this study, we characterized the gut microbiota fortnightly through 52 weeks of age in 3xTg-AD mice with mutations associated with familial AD [APP(Swe), PSEN1(M146V) (bearing a change of M to V at position 146), and MAPT(P301L)], modeling amyloid-β plaques and hyperphosphorylated tau and their genetic background (B6129F2/J) (wild type [WT]). Here, MAPT is linked to Alzheimer disease.