Effect of nutritional method on adaptation of the intestinal remnant after massive bowel resection

Adaptation of the intestinal remnant with hypertrophy/hyperplasia and increased absorption occurs, ultimately, after massive bowel resection. During the early postresection period, the rate of the adaptational process may be influenced by the method of nutritional support. Nutrients given by mouth may support a strong stimulus for hypertrophy but may be incompletely absorbed from the short intestinal remnant. Intravenous nutrition, while eliminating the need for intestinal absorption, may not support the hypertrophic process of that remnant. We tested the effect of different nutritional methods on the hypertrophic and functional adaptation of the intestinal remnant after 90% resection in the rat. The methods included oral feeding with regular rat chow, oral feeding with elemental diet, intravenous nutrition, and a combination of intravenous nutrition and oral feedings. Full thickness intestinal wall wet weight and mucosal wet weight, as well as in vivo L-valine absorption, were measured 9 days after operation. Resected subgroups were compared to sham-operated controls receiving similar diets. Increase in the weight of the intestinal remnant and its mucosa was noted in all resected subgroups receiving oral diets. Valine absorption per unit length and/or unit weight was significantly decreased in rats receiving oral diets alone and rats receiving a combination of intravenous and oral elemental diet. Significant increase in intestinal and mucosal weight without decrease in valine absorption was demonstrated in the animals receiving a combination of intravenous nutrition and regular chow diet. The results suggest that a combination of intravenous nutrition and ad libitum oral feedings with regular diet may represent the best method of nutritional support in the early postresectional period.