The extraction and analysis of fBEVs. Stools in the same weight from Control, DM, DM+AB and DM+FMT rats were collected to extract fBEVs, which were resuspended in equal volumes of PBS. (A) TEM was applied to observe fBEVs (scale bar, 100 nm, original magnification × 40k). (B) NTA was used to determine the size distribution of fBEVs from different groups. (C-D) Concentrations of fBEVs were quantified by the NTA (n=5). (E-F) Total protein of fBEVs was quantified by the BCA protein assay (n=5). (G-J) The outer membrane protein ompF in equal volumes of purified fBEVs suspension was measured by Western blot analysis to determine the amount of OMVs in the gut (n=5). *P < 0.05; **P < 0.01; ***P < 0.001.