|Burrin, Douglas - Doug|
|Van Goudoever, Johannes|
Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2003
Publication Date: 9/1/2003
Citation: BURRIN, D.G., STOLL, B., CHANG, X., VAN GOUDOEVER, J.B., FUJII, H., HUTSON, S., REEDS, P.J. PARENTERAL NUTRITION RESULTS IN IMPAIRED LACTOSE DIGESTION AND HEXOSE ABSORPTION WHEN ENTERAL FEEDING IS INITIATED IN INFANT PIGS. AMERICAN JOURNAL OF CLINICAL NUTRITION. 2003. v. 78. p. 461-470. Interpretive Summary: Doctors often put prematurely born babies on an intravenous feeding method called total parenteral nutrition (TPN), because they can't digest food given by mouth. Many studies have shown that after babies are fed by TPN for awhile, their gut shrinks to half the size it would have been if they were fed by mouth. We wanted to know whether, despite the fact the gut is so much smaller after a period of TPN, it is able to function normally. Since piglets are good animal models to study infant digestion, we took two groups of piglets and fed one group by TPN and the other by mouth with a formula, for about a week. Then we gave both groups formula by mouth. We wanted to know whether the TPN-fed group could digest and absorb nutrients as well as the other group. We put substances called tracers in the formula so we could trace the pigs' rates of digestion and absorption. We found that the protein was digested normally and the amino acid absorption rate was relatively normal in the TPN-fed group. However, the TPN-fed pigs only digested half the lactose intake relative to the other group. Also, they couldn't absorb all the glucose produced by the lactose digestion. Therefore, there was a defect in the carbohydrate digestion and absorption processes. For some time, it has been believed that being born prematurely causes babies to have a problem absorbing lactose, which can lead to serious illness. Our results suggest that this problem may not only be due to the fact the babies are born prematurely, but possibly because they were fed by TPN for a period of time before they were fed by mouth. This is information could lead to new feeding strategies to prevent feeding problems in premature infants.
Technical Abstract: BACKGROUND: Preterm infants often receive total parenteral nutrition (TPN) before enteral feeding. Although TPN has been linked to mucosal atrophy, its effects on intestinal digestion, absorption, and metabolism are unknown. OBJECTIVE: Our aim was to determine the effects of TPN on rates of intestinal nutrient absorption and metabolism in infant pigs after initiation of enteral feeding. DESIGN: Piglets were surgically implanted with catheters in the carotid artery, jugular vein, portal vein, and duodenum; an ultrasonic blood flow probe was inserted in the portal vein. Piglets were given TPN (TPN group) or enterally fed formula (enteral group) for 6 d. On day 7, both groups were enterally fed a milk-based formula, and the net portal absorption and metabolism of enteral [(2)H]glucose and [(13)C]leucine were measured. RESULTS: After enteral feeding began, portal blood flow increased by 27% and 41% above the basal rate in the enteral and TPN groups, respectively; oxygen consumption remained lower in the TPN group. During enteral feeding, the net portal absorption of glucose was lower in the TPN group and that of galactose was not significantly different between the groups; lactate release was higher in the TPN group. Portal absorption accounted for only approximately 37% of galactose intake in both groups. The TPN group had lower net portal absorption of arginine, lysine, threonine, and glycine. The portal absorption of dietary leucine was not significantly different between the groups; the arterial utilization and oxidation of leucine were significantly lower in the TPN group. CONCLUSION: Short-term TPN results in decreased lactose digestion and hexose absorption and increased intestinal utilization of key essential amino acids when enteral feeding is initiated in piglets.