Abstract
Objective
To quantify glutamine use by viscera drained by the portal vein in neonatal calves and to determine whether uptake could be stimulated by long-term IV infusion or long-term use of oral supplements.
Animals
4 healthy neonatal calves.
Procedure
A femoral artery, jugular vein, and the portal vein were surgically cannulated in each calf. Blood flow in the portal vein was measured, using an ultrasonic transit-time flow probe. Calves were given an IV infusion of glutamine on days 6, 8, and 10 after surgery. Before the first infusion, calves were fed a diet of milk only. The diet was supplemented with glutamine for the second and third infusions. Glutamine was administered via the jugular vein during a 5-hour period. Venous and arterial blood samples were collected every hour for 5 hours.
Results
During glutamine infusion, uptake of glutamine by viscera drained by the portal vein increased in association with increased production of ammonia. Glutamine supplementation of the diet did not alter glutamine uptake. Glutamine infusion did not increase viscera uptake of indispensable amino acids. Longterm use of glutamine supplements or infusion of glutamine for periods of more than 1 hour increased glutamine uptake by viscera. Arterial leucine concentration and uptake of leucine by the viscera decreased during glutamine infusion, indicating that leucine became the limiting factor.
Conclusion
Glutamine administration (supplements or infusions) to calves may require that a mixture of amino acids be provided to improve effectiveness.
Clinical Relevance
Glutamine may be beneficial in treatments designed to promote intestinal healing in diarrheic calves. (Am J Vet Res 1999;60:446-451)
