Lysine kinetics in preterm infants: the importance of enteral feeding
INTRODUCTION: Lysine is the first limiting essential amino acid in the diet of newborns. First pass metabolism by the intestine of dietary lysine has a direct effect on systemic availability. We investigated whether first pass lysine metabolism in the intestine is high in preterm infants, particularly at a low enteral intake. PATIENTS AND METHODS: Six preterm infants (birth weight 0.9 (0.1) kg) were studied during two different periods: period A (n = 6): 40% of intake administered enterally, 60% parenterally; lysine intake 92 (6) micromol/(kg x h); and period B (n = 4): 100% enteral feeding; lysine intake 100 (3) micromol/(kg x h). Dual stable isotope tracer techniques were used to assess splanchnic and whole body lysine kinetics. RESULTS: Fractional first pass lysine uptake by the intestine was significantly higher during partial enteral feeding (period A 32 (10)% v period B 18 (7)%; p<0.05). Absolute uptake was not significantly different. Whole body lysine oxidation was significantly decreased during full enteral feeding (period A 44 (9) v period B 17 (3) micromol/(kg x h); p<0.05) so that whole body lysine balance was significantly higher during full enteral feeding (period A 52 (25) v period B 83 (3) micromol/(kg x h); p<0.05). CONCLUSIONS: Fractional first pass lysine uptake was much higher during partial enteral feeding. Preterm infants receiving full enteral feeding have lower whole body lysine oxidation, resulting in a higher net lysine balance, compared with preterm infants receiving partial enteral feeding. Hence parenterally administered lysine is not as effective as dietary lysine in promoting protein deposition in preterm infants.
|Keywords||*Enteral Nutrition, Dietary Proteins/administration & dosage/pharmacokinetics, Female, Humans, Infant Nutrition/physiology, Infant, Newborn, Infant, Premature/*metabolism, Intestinal Absorption, Lysine/administration & dosage/*pharmacokinetics, Male, Oxidation-Reduction, Parenteral Nutrition, Research Support, Non-U.S. Gov't|
van der Schoor, S.R., Reeds, P.J., Stellaard, F., Wattimena, J.D., Sauer, P.J.J., Büller, H.A., & van Goudoever, J.B.. (2004). Lysine kinetics in preterm infants: the importance of enteral feeding. Gut (English Edition): an international journal of gastroenterology & hepatology. Retrieved from http://hdl.handle.net/1765/8284