Plasma malondialdehyde, biochemical and haematological parameters in standardbred horses during a selected field exercise test

Abstract

The aim of the present study was to determine changes in plasma malondialdehyde (MDA) concentration and haematological and biochemical profiles in 10 clinically healthy standardbred horses subjected to a selected field exercise test. Correlations between plasma MDA, the main lipid peroxidation end-product, and muscle enzymes: creatine kinase (CK) and aspartate aminotransferase (AST) were determined in serum samples. Venous blood samples for determination of selected blood parameters were collected, immediately post exercise, and 24 and 48 hours post exercise. Significant changes in most of the biochemical and haematological parameters determined immediately after exercise reflect the normal physiological response of horses to a selected field exercise test. Most of these parameters returned to or close to the stall values within 48 hours. The concentration of plasma MDA increased immediately post exercise, though not significantly; however it increased significantly 24 hours post exercise and reached its highest value 48 hours post exercise. Thus exercise-induced oxidative stress is evidenced by increased lipid peroxidation. From the rapid decline of serum CK activity post exercise and the absence of significant correlations between MDA and serum muscle enzymes, we concluded that the selected field exercise test caused no permanent alteration in muscle cell integrity or muscle damage.