EFFECT OF DIETARY-CHOLESTEROL AND CARBOHYDRATE ON SMALL INTESTINAL STRUCTURE AND FUNCTION IN PREMATURELY WEANED RATS

A study using the prematurely weaned rat as a model for the pig was undertaken to determine the effect of dietary cholesterol and carbohydrate source on small intestinal structure and function. Duodenal and jejunal samples were obtained at 18, 24, and 30 d of age from rats weaned at 15 d of age and from unweaned rats at 15, 18, 24, and 30 d of age. Four 20% CP diets were formulated: two diets used lactose and glucose as the carbohydrate source and two used sucrose and starch as the carbohydrate source; 1% cholesterol was substituted for either glucose or starch in one of each diet type. The unweaned rats consistently gained weight at a faster rate (P < .01), had greater concentrations of Alcian blue (AB+) and periodic acid-Schiff (PAS+) goblet cells (P < .03), and had more favorable vilus height than did the weaned rats. The animals fed cholesterol tended to gain more weight, had more AB+ and PAS+ goblet cells (P < .03), and had longer villi than did those not fed cholesterol. Lactase activities tended to be greater in the unweaned rats. Sucrase activities were greater in the weaned rats at 18 d (P < .02). The data indicate that the addition of cholesterol to weaning diets is beneficial in maintaining small intestinal integrity.