Effects of glucose oxidase on intestinal morphology of ducks infected by Escherichia coli. (A) The villus height in jejunal of ducks. (B) The crypt depth in jejunal of ducks. (C) The ratio of villus height to crypt depth in jejunal of ducks. Means with different letters are different (P < 0.05). Abbreviations: ANT, antibiotic group, diet supplemented with virginiamycin at 30 mg/kg; CON, control group, basal diet; GOD, glucose oxidase, diet supplemented with glucose oxidase (1,000 U/g) at 200 U/kg; V:C, the ratio of villus height to crypt depth.