Abstract
The objective of the study was to assess ratio of oxidation to antioxidation in the blood of horses in selected equine diseases. The study was conducted on 47 Polish half-breed horses (36 mares, six stallions, and five geldings) aged 2 to 16 years. Nineteen mares were diagnosed with endometritis, seven horses with symptoms of colic, and six with upper respiratory tract infection. The remaining clinically healthy horses (n=15) served as control. The following parameters were measured: oxygen metabolism in neutrophils using a chemiluminescence (CL) method, total antioxidant status (TAS) of blood plasma, as well as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase activity in whole blood. The results demonstrate increased CL of neutrophils in mares with endometritis, as well as in horses with symptoms of colic. This finding was associated with decreased values of SOD, GPx, and TAS (chiefly in mares with endometritis), which suggests oxidative stress. These results underscore the importance of a broader use of oxidant/antioxidant status assessment in studies of the pathogenesis and pathomechanisms of equine diseases.