OXIDATIVE STRESS DURING EXERCISE IN RACEHORSES - RELATIONSHIPS BETWEEN NUTRITION, TRAINING AND BIOCHEMICAL DEFENSES AGAINST FREE-RADICALS

It has been suggested that the pathogenesis of exercise-induced myopat hies and hemolysis in horses may be related to oxidative stress caused by free radicals. As acute strenuous exercise and chronic exercise tr aining increase the consumption of natural antioxidants, we decided to evaluate the suitability of dietary supplementation with antioxidants during training. Three year old Maremmana stallions were randomly sel ected from two groups while undergoing special training: one group was fed with a diet enriched with 20 mu g/kg of body weight of selenium p er day. The horses were followed by testing: 1) some enzymatic activit ies both in the erythrocytes and plasma; 2) plasma vitamin E content a nd 3) red blood cell membrane composition. From the results obtained o ne may deduce that the diet of the first group of animals studied was unable to support the increased antioxidant defense needs caused by th e training. However, it seems that there was no direct relationship be tween antioxidant defences and muscle damage.