Antenatal intestinal adaptation with experimental jejunoileal atresia.

Jejunoileal atresia without significant shortening of total intestinal length, was created in five date-bred Dorset ewes by devascularizing a 15 cm segment of fetal intestine at 90-100 days gestation. Light microscopy showed mucosal hypertrophy distal to the atresia with almost total obliteration of the lumen by tail, feathery-shaped villi similar to those observed in newborns with jejunal atresia. Scanning electron microscopic views of the proximal mucosa showed the villi to be thicker, more segmented and tended to congregate compared to normal villi and those distal to the atresia. No evidence of microvillus, intracellular or capillary membrane change or injury could be identified to explain the functional secretory state.