Validation of assays for measurement of oxidant compounds in saliva of pigs: Thiobarbituric acid reactive substances (TBARS), carbonyl, and reactive oxygen species (ROS).

Thiobarbituric acid reactive substances (TBARS), carbonyls and reactive oxygen species (ROS) are oxidant compounds that can provide useful information on the oxidative status. Pigs can be affected by oxidative stress in different situations including physiological conditions such as lactation and also in different diseases, and the measurement of these three analytes in saliva could be potentially useful as biomarkers of the redox status in this species. Assays for the measurement of TBARS and carbonyls by spectrophotometry and ROS by luminol-based chemiluminescence in pigs' saliva were analytically validated and were applied in saliva of pigs after an in vitro incubation with different doses of ascorbic acid (AA). All the assays showed a satisfactory analytical precision and accuracy. The 240 h-incubation of saliva samples with 60 mM of AA induced to an increased TBARS and carbonyls production. TBARS, carbonyls and ROS can be estimated in saliva of pigs by the assays validated in this report. In addition, these assays can detect changes in the concentration of these analytes associated to incubation of saliva samples with AA.