Effects of parenteral and enteral nutrition on postnatal development of the small intestine and pancreas in the rabbit.

Although TPN is used frequently in young infants, little information is available regarding its effect on postnatal development of the gut. The effect of total parenteral nutrition (TPN) and intragastric (IG) alimentation on ontogeny of the small intestine was examined in infant rabbits starting at 10-12 days. Animals were killed at 17-19 days. Body weight, organ weight and weight of segments of proximal, mid and distal small intestine were measured. Intestinal mucosa was scraped, weighed and homogenized for estimation of protein, DNA and disaccharidases. Na+ transport was examined in short-circuited jejunum. Weight gain was similar in controls, sham-treated and TPN animals, but was significantly reduced in IG animals. TPN induced precocious development of sucrase and maltase activity and glucose-stimulated Na+ transport, despite causing a significant decrease in mucosal weight and DNA and pancreatic amylase. IG alimentation also induced precocious development of sucrase, maltase and glucose-stimulated Na+ transport. Thus TPN, despite producing mucosal atrophy and decreased pancreatic exocrine development, stimulates accelerated postnatal maturation of the small intestine.