Growth of the fetal sheep small intestine

Body growth of the sheep fetus was studied over the period 60 to 145 days gestation (term is approximately 147 days). Fetal length increased more rapidly than did weight. Growth was also assessed in the component tissues of the intestinal wall. In all cases, growth was more rapid late in gestation. Comparison of the mean size or density of intestinal components at two ages (115 and 136 days gestation) revealed significant increases in proximal regions for the following parameters: intestinal diameter, total wall thickness, mucosal thickness, villus height, crypt depth, villus base width and crypt density. In distal regions significant increases were noted in all of the above with the exception of villus base width and crypt density. The magnitude of age related changes was most often greater in proximal regions. This suggests that morphological maturation proceeded at a faster rate in proximal portions of the small intestine.