Fig. 6

a PCoA and adonis test based on the Bray–Curtis distance of SCFA compositions in the caecum digesta between laying hens with and without dietary MF. b SCFAs with significantly different contents in the caecum digesta between laying hens with and without dietary MF. c PCoA and adonis test based on the Bray–Curtis distance of AA compositions in the caecum digesta between laying hens with and without dietary MF. d AAs with significantly different contents in the caecum digesta between laying hens with and without dietary MF. e The heatmap shows the abundance of genes related to the biosynthesis of SCFAs and the urea cycle in the caecum digesta of laying hens with and without dietary MF. Different lowercase letters in each box of the same subfigure represent significant differences between laying hens in different groups (Student’s t test, p < 0.05)