Effect of fortification of extender with α-terpineol and rosemary essential oil on post-thaw ovine semsen quality.

The goal of the present study was to assess the viability of the cryopreserved ovine (Ovis aries) semen, upon supplementation with α-terpineol and rosemary essential oil (Rosmarinus officinalis). The collection of the semen from six rams formed the pool, collected once a week during 7 weeks. The diluted semen was packed into straws (0.25 ml) and frozen in a TK 3000® device. Both α-terpineol and rosemary essential oil were added in the concentrations of 6.25, 12.5 and 25 μg/ml to the TRIS-yolk extender forming six experimental groups; the control group received only the TRIS-yolk extender. The samples were analyzed after thawing regarding motility and vigor, integrity of the plasmatic membrane, thermoresistance test (TT), mitochondrial membrane potential, acrosomal integrity and computer-assisted semen analysis (CASA). The levels of the thiobarbituric acid reactive substances were also analyzed. According to the results obtained with the addition of the concentrations of 6.25, 12.5 and 25 μg/ml of α-terpineol, significantly reduced the parameters assessed through CASA (VSL, LIN and WOB) and TT. Rosemary essential oil did not have deleterious effects on the spermatozoa and did not reduce the oxidative stress in the concentrations studied, although it presented absolute values higher than those of the control in several parameters. Alpha-terpineol in the concentrations studied was not able to reduce the oxidative stress and had toxic effect over the ovine spermatozoa.