Effect of restricting a balanced diet on rat intestinal disaccharidase activity and intestinal architecture.

The effects of malnutrition on the gastrointestinal tract have been previously investigated in animal models using dietary protein restriction. Because malnutrition is clinically a consequence of reduced dietary intake of all macronutrients, we investigated the effect of restricting a balanced diet on intestinal disaccharidases and histologic conditions of rats. Our diet-restricted animals gained less weight (13 +/- 9 gm) than the control animals (158 +/- 27 gm) over the 5-week study. The proximal, middle, and distal small intestinal segments from the experimental animals had reduced mucosal protein content (15 +/- 4 mg vs. 24 +/- 7 mg). In these segments the total amount of maltase was slightly decreased, whereas sucrase and lactase activities were normal or increased. The intestinal villus/crypt ratios were similar in the experimental and control animals. Mucosal cell height was significantly reduced in the diet-restricted groups; however, cell width was normal. We conclude that severely diet-restricted animals have mucosal protein loss caused in part by reduced cell height, but that the disaccharidase enzyme activities are normal. Diet-restricted animals appear to have sufficient intestinal enzymes to support a normal amount of disaccharide hydrolysis.