Fig. 6

The bacterial taxa and microbial genes taking part in the biosynthesis and metabolism of sex steroid hormones and comparisons of their abundances and its metabolites between normal return and non-return sows. A Biosynthesis and metabolism of pregnenolone and progesterone. Microbial genes (K10251, K00038, and K12343) participating in the metabolism of progesterone were up-regulated in normal group. Moreover, Prevotella spp. and Limosilactobacillus reuteri carrying K12343 and K00038 genes also showed significant enrichment in normal group, suggesting a promotion of progesterone degradation in normal group. However, cholesterol, pregnenolone, and 11beta,17alpha,21-trihydroxypregnenolone and 7alpha-hydroxypregnenolone had higher concentrations in feces of non-return sows. B Biosynthesis and metabolism of testosterone. As described in A, microbial gene K12343 participating in the metabolism of testosterone and androstenedione, and Prevotella spp. carrying K12343 had higher abundances in normal sows. C Biosynthesis of estrogens (estradiol-17beta, estrone and estriol). Microbial gene K10251 involved in the mutual transformation of estrogens was enriched in normal sows. Boxplots show the differential abundances of bacterial species, microbial genes and fecal metabolites between non-return and normal return sows. Red represents the metabolites that were significantly enriched in non-return group, and blue represents bacterial species, microbial genes and metabolites that were significantly enriched in normal group. Wilcoxon rank sum test was used for differential analysis of bacterial species and microbial genes, and Student's t-test was used for differential analysis of fecal metabolites. ns, FDR > 0.05, ^*FDR < 0.05, ^**FDR < 0.01, ^***FDR < 0.001, ^****FDR < 0.0001. Gut bacterial species carrying microbial genes involved in this pathway have also been highlighted. And the solid lines between metabolites represent direct and previously confirmed pathways and the dashed lines represent indirect or unknown pathways