Cooling of porcine semen in an extender supplemented with carvacrol

Abstract

The addition of antioxidants in boar semen is an alternative to mitigate the reduction of sperm quality during preservation. To evaluate the effect of carvacrol on cooling of boar semen. Fifteen ejaculates from five boars were extended in MR-A® with 0, 5, 10, 15, 15, 20, 25 and 30 μM of carvacrol (C) and were cooled for 5 days at 16°C. Sperm motility and kinetics were evaluated with computer-assisted semen analysis (CASA). At 0 and 96 h, membrane functionality was determined by hypoosmotic test; reactive oxygen species (ROS) production and total antioxidant capacity (TAC) by spectrofluorimetry and mitochondrial membrane potential (Δ¥M) by flow cytometry. Linear models, regression analysis and comparison of means by Duncan test, were conducted. The addition of carvacrol did not influence sperm motility, but at low concentrations decreased ROS production, whereas 30 μM C reduced the membrane functionality and 25 μM C decreased Δ¥M. In addition, regression coefficients showed that C produced a lower rate of decrease in different parameters of sperm motility and kinetics. During cooling there is a reduction in sperm quality due to the excessive production of ROS, generating oxidative stress and affecting cell permeability and functionality. In this study, it was possible to demonstrate the protective activity of C as a molecule capable of neutralizing free radicals. In addition, it has been proposed that C is also capable of reducing peroxyl radicals, superoxide radicals, hydrogen peroxide and nitric oxide. Carvacrol can mitigate the reduction of boar semen quality during the storage period under cooling conditions. Likewise, it can reduce ROS production and modulate the mitochondrial activity of porcine sperm.

Keywords: antioxidant; boar semen; carvacrol; cooling; spermatozoa.