Changes in Oxidative Status Biomarkers in Saliva and Serum inthe Equine Gastric Ulcer Syndrome and Colic of IntestinalAetiology: A Pilot Study

Abstract

Changes in the oxidative status of the blood of horses suffering from gastric ulcers and colicof intestinal aetiology (CIE) have been reported. However, saliva can also be a source of biomarkersof oxidative status. Therefore, this study aims to validate automated assays for the measurement ofoxidative status biomarkers (ferric reducing ability of saliva/serum—FRAS/FRAP, cupric reducingantioxidant capacity—CUPRAC, the Trolox equivalent antioxidant capacity—TEAC, uric acid, andadvanced oxidation protein products—AOPP) in the saliva and serum of horses, to assess theirchanges in the different ulcer gastric diseases (squamous—ESGD and glandular—EGGD) and CIE,and to evaluate their relationship with serum amyloid A (SAA), adenosine deaminase (ADA), andthe systemic inflammatory response syndrome (SIRS) status. The assays showed a low imprecisionand good linearity with enough sensitivity in both fluids. In EGGD, higher levels of FRAS, uric acid,and AOPP in saliva were observed compared to the healthy group, correlating with the salivaryADA levels. Horses with CIE showed increases in uric acid concentrations in serum associated with heir SIRS status and outcome of the disease. In conclusion, analytes related to the oxidative statuscan be measured in the saliva and serum from horses by automated assays, and some of them canpotentially be assessed as biomarkers in horses with gastric ulcers and CIE