Assessment of oxidative stress biomarkers in exhaled breath condensate and blood of Thoroughbred foals

This study reports preliminary data on systemic and local biomarkers of oxidative stress (OS) in Thoroughbred foals. Blood and exhaled breath condensate (EBC) were sampled from 13 foals on two farms. Values of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), antioxidant barrier (OXY-ads), thiol antioxidant barrier (SHp) and advanced oxidation protein products (AOPPs) were determined in blood, while EBC samples were assayed for hydrogen peroxide (H2O2) levels. ic and local OS biomarkers did not differ between farms and gender. Increased oxidative stress index (OSI) values in a foal recovering from pneumonia and elevated H2O2 in EBC coupled with low SHp and elevated AOPPs in the blood of a foal with overt upper respiratory tract disease suggested that the OS markers measured in this study may relate to the respiratory health status of foals.