Changes in Acute Phase Response Biomarkers in Racing Endurance Horses

SIMPLE SUMMARY: Sport horses competing in exhausting sporting events require special attention to ensure their welfare. Changes in acute phase response induced by both aerobic and anaerobic exercise are studied for understanding the physiological response to strenuous exercise. We suggest that endurance racing induces acute phase response in horses, characterized by a decrease in calprotectin and haptoglobin values, and an increase in concentrations of ceruloplasmin and albumin, with more pronounced changes noted at races with higher average speeds, suggesting the need for thorough horse monitoring during exhausting races. ABSTRACT: This study aimed to evaluate if exercise-induced acute phase response (APR) occurs in endurance horses in response to the race. The study included 23 horses competing in an endurance competition with a successfully passed clinical examination before the race. Blood samples were collected before the start and within 30 min after the end of the race. Haematological and biochemical tests were performed and correlated to acute phase biomarkers changes. Values of calprotectin and haptoglobin (Hp) decreased after the races compared to values before, while concentrations of ceruloplasmin and albumin recorded a significant increase. Greater changes in calprotectin values were noted in Arabian horses compared to other breeds. Values of Hp showed a significantly greater decrease after longer races. Based on study results, endurance racing induces APR in horses characterised by significant changes in selected acute phase biomarkers. More pronounced changes were noted at races with higher average speeds, suggesting the need for thorough horse monitoring during exhausting races.