Assessment of oxidative stress biomarkers in exhaled breath condensate and blood of dairy heifer calves from birth to weaning.

The balance between oxidants and antioxidants may be impaired in neonatal calves but only limited information is available on physiological changes in oxidative biomarkers in healthy calves. The aim of this study was to measure biomarkers of oxidative stress (OS) in calves from birth to weaning. Eighteen, healthy, female Holstein-Friesian calves were used in the study. Blood and exhaled breath condensate (EBC) samples were taken on the day of birth (Week 0) and then at Weeks 6, 12 and 18. Reactive oxygen metabolites (ROMs) and biological antioxidant potential (BAP) were determined on fresh blood and the degree of OS was expressed as an oxidative stress index (OSI), where OSI = ROMs/BAP × 100. Plasma concentrations of antioxidant barrier (OXY), thiol antioxidant barrier (SH), advanced oxidation protein products (AOPP), albumin, and non-esterified fatty acids (NEFA) were also measured, as was hydrogen peroxide (H2O2) concentration in EBC. Plasma concentrations of ROMs were relatively stable during the trial; AOPP concentration progressively decreased reaching its lowest values on Week 18. Albumin, SH and OXY concentrations progressively increased from birth to weaning. Concentrations of NEFA in plasma and H2O2 in EBC were relatively stable but peaked in Week 18. The results indicate that antioxidative defence not only increases with time in the plasma of new-born calves but also that it is related to protein oxidation processes. Furthermore, the data support the use EBC H2O2 as a novel biomarker to assess respiratory OS in calves.

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 (H(2)O(2)) levels. Systemic 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 H(2)O(2) 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.