New model of hyponutrition in weanling rabbit: Short term effects on intestinal growth, morphology, and disaccharidase activities

This study was undertaken to define morphological and biochemical characteristics of intestinal growth during short term hyponutrition in weanling rabbits. A new model was sought so that isolated small bowel could be studied in organ culture. Underfed rabbits maintained a stable weight, while matched controls steadily gained weight over a two week period. Serum protein and albumin concentrations remained unchanged in underfed animals, but total intestinal mucosal wet weights were reduced, as were total DNA and protein content per 5 cm segment. The protein/DNA ratio remained unchanged by hyponutrition, suggesting that epithelial cell size was constant; epithelial cell counts confirmed that the jejunal villi were significantly decreased in height. In contrast, specific activities of maltase and sucrase were increased over control values in underfed animals, although total enzyme activity per segment did not change. These data confirm the importance of specific dietary components in the preferential maintenance of intestinal enzyme activities, even during undernutrition. The experiments also demonstrate that a well-defined state of hyponutrition can be established in weanling rabbits by short term underfeeding, and that jejunum from such animals can be maintained in organ culture under defined conditions. This model should prove useful for the in vitro investigation of the effects of underfeeding on intestinal function.