Epsilon Archive for Student Projects

Abstract

The aim of the project was to study the effect of oral administration of glucose and leucin on the resynthesis of muscle glycogen after intense exercise in Standardbred trotters.

In a crossover design, 11 Standardbred trotters performed a standardized exercise test on two occasions in order to deplete muscle glycogen. The exercise test comprised a warm up period, 7 repeated bouts of exercise on an uphill 500 m slope, and a recovery period. After the exercise test horses received: 1) a solution of glucose and leucine via a nasogastric tube at 0 minutes and at 240 minutes post exercise and a single bout of glucose at 120 minutes post exercise or 2) water (placebo) at 0, 120 and 240 minutes. Blood samples for measurement of glucose and insulin concentrations were collected at rest, when the horses returned to the stables directly after exercise and throughout the 6 hour recovery phase. During the first recovery hour, samples were collected every 15 minutes and then every 30 minutes over the next 5 hours. Muscle biopsies were taken at rest prior to exercise, within 15 minutes after exercise and at 3, 6, and 24 hour after exercise.

Horses that received glucose and leucin had elevated concentrations of serum glucose and plasma insulin compared to the placebo group during the 6 hour recovery period. However, there were no statistically significant differences in glycogen resynthesis between the glucose and leucine group compared to the placebo group during the 24 hour post exercise period. The results from this study show that the rate of muscle glycogen resynthesis is not enhanced by oral administration of glucose and leucine after intense exercise in horses.