Evaluation of Biological Indicators of Fatigue and Muscle Damage in Arabian Horses After Race.

The research conducted a comprehensive biochemical analysis on six Arabian horses to monitor changes associated with exercise-induced muscle fatigue during races. Several biochemical parameters and muscle damage biomarkers were measured before and after the races, revealing alterations in antioxidant enzymes and increased but natural-range levels of muscle damage biomarkers as a sign of fatigue.

Study Design and Methodology

• The researchers set out to investigate the impact of physical exertion, in the form of two races (1,250 and 1,400 meters), on Arabian horses ranging in age from 3 to 6 years old.
• Through collecting and analysing blood samples at specified points of time—1 hour before the race, immediately after, 1 hour post-race, and 24 hours post-race—the team sought to evaluate the changing biochemical parameters that indicate muscle stress and fatigue.

Measurements and Findings

• The blood samples were examined for a variety of markers, including antioxidant enzymes like catalase (CAT), superoxide dismutase, and glutathione peroxidase (GPX), as well as for indicators of oxidative stress like the malondialdehyde and protein carbonyl levels and total antioxidant capacity (TAC).
• The study also monitored muscle damage biomarkers such as aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) activities, and myoglobin. These are typical measurements used to estimate muscle stress in physically active organisms.
• The researchers found that CAT activity and plasma TAC had increased immediately after the race and then gradually decreased, indicating temporary reliance on antioxidant mechanisms. Meanwhile, GPX activity in red blood cells peaked 1 hour before the race.
• The superoxide dismutase activity showed a steady increase after the race, suggesting an elevated antioxidant response.
• AST, a common marker for muscle damage, significantly increased in plasma levels right after the race and remained elevated 1 hour post-race.
• The activities of LDH and CK, two more indexes of muscle damage, reached their highest value 1 hour after the race.

Conclusion

• These results suggest a pattern of altered antioxidant enzyme activity under conditions of fatigue, reflected primarily in the antioxidant enzymes’ responses to the racing activity.
• In terms of muscle damage, increased levels of specific biomarkers were observed, signifying muscle stress. However, the researchers found these increases to be within standard ranges, leading them to conclude that the physical exertion did not cause significant muscle damage in the horses.