A) C57BL/6 female conventional (n=5) mice and Swiss Webster GF (n=3–4) mice fed indicated diets were euthanized and distal colon cut into small pieces and cultured overnight. The supernatant was used to measure IL-22 by ELISA. B–I) IL-22KO (n=13) male mice were fed chow, HFD supplemented with cellulose (HFD-200 Cell) or inulin (HFD-200 Inul) for 4 weeks. B) Colon length. C) Colon weight. D) Epididymal fat pad. E) Mesenteric fat. F–G) Mice (n=10) were administered glucose, 2 g/kg intraperitoneally following an overnight fast. Blood glucose levels were measured at the indicated time point (F) and area under curve (AUC) calculated (G). H–I) Mice (n=5) were fasted 5 h, the glucose was measured at 0 (H), 30, 60, 90 min after intraperitoneally injected with insulin (I). Data were expressed as mean ± SEM. Statistical significance was assessed by unpaired Student t test. *p<0.05; **p<0.01; n.s, not significance. See also Figure S6 and S7