Fig. 6

Differentially abundant faecal bacterial taxa in response to the addition of dietary haem and/or calcium carbonate. a Classified differentially abundant taxa between rats fed with a haem-enriched diet and control diet. Log2FoldChange (HEM vs. CON) = log₂(HEM/CON) is plotted on the X-axis. Phylum is indicated using colour codes. Features were considered significant if their adjusted post-test P value was < 0.01 (haem effect against other three groups). b Circular cladogram generated from LEfSe analysis showing the most differentially abundant taxa enriched in microbiota from rats fed with control (red) or haem (green) diets. c Classified differentially abundant taxa between rats fed a haem-enriched diet and other diets. The taxa were identified using a 2 × 2 factor design by sorting the interaction term corresponding to haem-affected taxa, for which the addition of calcium restored the initial levels observed in the control diet. Log2FoldChange (HEM vs. (CON and HEM-Ca) = log₂(HEM/(CON and HEM-Ca)) is plotted on the X-axis. Phylum is indicated by colour codes. Features were considered significant if the adjusted P value of the interaction term was < 0.01. d Cladogram showing the most differentially abundant taxa enriched in microbiota from rats fed with haem (red) or haem-calcium (green) diets. LDA scores > 3 and significance of alpha < 0.01 determined by Kruskal-Wallis test. Corresponding LDA scores are presented in Additional file 2: Figure S4