(A–D) Analysis of microbiota community structure in SI5 lumen and mucosa of CD and 8-week WSD-fed mice by 16S rRNA gene sequencing. Principal-component analysis of β-diversity (Bray-Curtis dissimilarity) of bacterial communities in the luminal (A) and mucosal (B) compartments. Linear discriminant analysis (LDA) effect size identification of diet-enriched bacterial taxa (C). α-diversity (Shannon index) of bacterial communities (D).
(E) Schematic illustrating CD and WSD microbiota transfer (MT) into WSD-fed mice after antibiotics (ABX) treatment.
(F) Median relative abundance of all genus-level bacterial taxa impacted by WSD exposure (C) in the CD-fed SI5 microbiota (left panel) and CD-fed donor caecal contents microbiota (right panel) used for CD-MT gavage. Red line indicates a relative abundance of 1%.
(G) Relative abundance of three major bacterial taxa found in the SI5 microbiota in WSD-MT and CD-MT SI5 samples.
(H) Confocal z stacks showing x/z axis cross sections of ex vivo SI5 tissue (gray) and 1-µm microspheres (red) from WSD-MT and CD-MT mice; approximate mucus surface (green dashed line) indicated.
(I) Quantification of mucus thickness (upper) relative to villus tips (VTs) and relative barrier function (lower) based on data extracted from images shown in (H). Barrier function data are normalized to the WSD-MT group mean.
(J) Confocal z stacks showing x/z axis cross sections of ex vivo SI5 tissue (gray) and 1µm microspheres (red) from WSD-fed mice with (ABX) or without (H2O) supplemented in their drinking water; approximate mucus surface (green dashed line) indicated.
(K) Quantification of mucus thickness (upper) relative to villus tips (VTs) and relative barrier function (lower) based on data extracted from images shown in (J). Barrier function data are normalized to the WSD-H2O group mean. All image scale bars are 50 µm. Data show median and interquartile range for n = 4–5 (A–D, J–K) or n = 9–10 (E–I) mice per group. Significance by pairwise PERMANOVA (A, B) or Mann-Whitney (D, G, I, K) test (*p < 0.05, ns: not significant).