Fig. 2

Iron supplementation differentially alters gut microbiota in Apc^Min/+ mice receiving fecal microbiota transplantation from healthy controls (FMT-HC) and patients with colorectal cancer (FMT-CRC). A Distance-based redundancy analysis (RDA) of gut microbiota composition in fecal samples comparing the effect of dietary iron between FMT-HC and FMT-CRC mice. Relative abundances of microbial taxa at B phylum and C family levels. Significantly affected families after FDR correction exclusively in FMT-HC or FMT-CRC mice are framed in red. D Differential bacterial species between FMT-HC and FMT-CRC mice fed an iron sufficient (50 ppm) and iron excess (500 ppm) diet. (LEfSe, LDA > 3.0 and P < 0.05, FDR corrected). E Alistipes inops, and Faecalibaculum rodentium levels quantified by real-time PCR. F Proliferation of HT29 cells treated with culture broth (CTLR) or cell-free supernatants from A. inops or F. rodentium cultures. Bars are means ± SEM of n = 5 independent experiments. B, E Each symbol represents one mouse, FMT-mice (n = 13 (50 ppm); n = 13 (500 ppm)), FMT-HC (n = 24 (50 ppm); n = 26 (500 ppm)) and FMT-CRC (n = 25 (50 ppm); n = 27 (500 ppm)). Bars are means ± SEM. P values were obtained using student t-test for FMT-mice. For mice transplanted with human fecal samples (FMT-HC and FMT-CRC) the generalized estimating equations (GEE) to correct for covariance structure of mice from a same donor (n = 3 mice/donor) was used. *P < 0.05, **P < 0.01, ***P < 0.001, n.s.: non-significant