Evaluation of the ergogenic potential of two feed supplements in endurance horses

Abstract

During prolonged effort, such as endurance exercise, the main sources of energy production for ADP phosphorylation are non-structural carbohydrates and fats. The relative percentage utilization of these two main energy sources varies according to the intensity and duration of exercise. Another important energy source is muscle glycogen. During endurance races muscle glycogen is rapidly depleted. Supplemental concentrate feeding could increase the size of these muscle glycogen stores, which would result in more energy to perform work, and improved performance. The purpose of this study was to evaluate the potential effects of alternative feed supplements Schisandra chinesis and CLA in an attempt to improve the working capacity and performance of endurance horses. A study was conducted on 25 Arabian endurance horses at Hadaybit Asalem Stables in Dubai. These horses were all trained in a similar way for at least 20 days before the study commenced. The horses were randomly divided into four groups, namely CLA group, Control group, Schisandra group and a Combination group. These horses were subjected to an adaptation phase of 10 days during which time no feed supplements were fed (Day 0 - Day 9). Feed supplementation started on Day 10 and continued to Day 19 (10 days). Basal heart and respiration rates, as well as basal rectal temperatures, were recorded daily. Post exercise heart and respiration rates were recorded on days 0, 5, 10, 15 and 19. Blood samples were collected from the horses on days 0, 11 and 19. Pooled results indicate that Schisandra had the most pronounced effect on lowering pre-exercise basal heart rate values, as well as lowering post exercise heart rate values. CLA supplementation increased basal respiration rate, decreased blood glucose concentrations by improving glucose uptake from the blood and increased lactate dehydrogenase (LDH) concentrations, resulting in an increased ability of the body to clear lactic acid from the system. The combination treatment group had the highest post exercise respiration rates, most likely due to an increased metabolic rate. Comparisons of treatment effects between day 0 and day 19 suggest that Schisandra had the most prominent effect on lowering respiration rates, both basal and post exercise. CLA’s most prominent effect was the opposite, by increasing both basal and post exercise respiration rates. As these two supplements have opposite effects on respiration rate in horses, these two supplements should not be fed together.