Effects of dietary natural zeolite including plant extract on growth performance and intestinal histology in Aigamo ducks.

1. To investigate the growth performance and histological intestinal alterations of Aigamo ducks fed on dietary combinations of zeolite, plant extract and vermiculite (ZEM, 14-d-old Aigamo ducks were divided into 4 groups, with 3 replicates of 3 male and 3 female ducks. They were fed ad libitum on a basal commercial duck mash diet with 0, 0.1, 0.5 and 1.0 g/kg dietary ZEM for 63 d. 2. Body weight gain tended to be higher for the 0.1 and 0.5 g/kg ZEM groups than for the control group at 9 weeks. 3. In light microscopic observation, most values of the intestinal villus height, villus area, cell area and cell mitosis numbers were higher in the ZEM group than those of the control in all intestinal segments, and the duodenal villus height, cell area and cell mitosis of the 0.5 g/kg ZEM group, as well as jejunal cell mitosis in the 0.1 g/kg ZEM group, increased (P < 0.05). In the scanning electron microscope results, all ZEM groups showed protuberant epithelial cells and cell clusters on the villus apical surface of the duodenum and ileum. In the jejunum, villus gyri were frequently observed in the 0.1 g/kg ZEM group. These histological intestinal alterations suggest that intestinal villi and epithelial cellular functions might have been activated. 4. From the present results, dietary ZEM showed hypertrophied functions of intestinal villi and epithelial cells at the duodenum and ileum, and the 0.1 and 0.5 g/kg levels improved body weight gain. These suggest that the ZEM can be supplemented until a level of 1.0 g/kg.