Postweaning development of porcine small intestinal morphology and epithelial cell proliferation 1

Histomorphometry and cell proliferation are markers of intestinal development, which we investigated in pigs from weaning to slaughter at 5 different small intestinal sites. Furthermore, the impact of enteral deoxynivalenol (DON) exposure on intestinal morphology and proliferation was studied. Postweaning pigs of 4 categories (1, 4, 8, and 12 wk after weaning) were slaughtered (4-6 pigs/category) and intestinal wall was collected from the duodenum, proximal jejunum, mid jejunum, and proximal and terminal ileum. Villus height and crypt depths were measured on histological specimens, and cell proliferation was determined by immunohistochemistry (5'-bromo-2'- deoxyuridine-positive or phosphohistone H3-positive cells) in the crypt area. All pigs were fed either a control diet or a DON-contaminated diet (approximately 3 mg/kg feed), and data were analyzed for the effect of gut axis, age, and diet. Villus height was only marginally affected by intestinal site, age, or diet, but crypt depth and cell proliferation showed a distinct pattern along the small intestinal axis. In pigs, irrespective of age or diet, the duodenum exhibited the deepest crypts (P < 0.05) but the lowest count of proliferating cell, albeit the latter was not always statistically significant. Moreover, there was a strong age effect on crypt depth at the duodenal and upper jejunal level but not in the lower intestinal sections: crypt depth increased dramatically (P < 0.01) between 1 (294 μm), 4 (505 μm), and 8 wk after weaning (508 μm). There was no difference between the 4-wk-after-weaning animals and older animals. We could not confirm a positive relationship between crypt depth and proliferating cell count. The presence of dietary DON did not significantly modify the development of the small intestine with respect to villus height, crypt depth, or epithelial cell proliferation.