Figure 3. Compositions of the control, diabetic and insulin- treated diabetic microbiomes in the colon at domain, phylum, class and order levels.

The abbreviated and colour-coded taxa are indicated on the right side in systematic sequence. Two minor classes belonging in the phylum Firmicutes are marked only with colours. “Other sequences” are probably those of viruses not covered in the databases used. Taxa with very low (<1%) abundances are indicated to two decimal places. The diversity of the microbial community was increased significantly in the insulin-treated diabetic animals, members of the order Bacteroidales predominating. The order Enterobacteriales is shown at higher resolution in diabetes (3B). The presence of the Klebsiella in the diabetic samples was still clearly seen although not as markedly as in the case of the ileum. Insulin promoted the abundance of the order Bifidobacteriales.