Xantana como aditivo crioprotetor externo para congelamento de sêmen ovino

Abstract

The xanthan gum can contribute to reduce the formation of ice crystals in the sperm freezing solution, facilitating the preservation of sperm viability after thawing. However, there is no information about the use of xanthan gum as an additive for cryoprotection of ram sperm. This study aimed to determine the effect of three different concentrations of xanthan (0.15%, 0.20% and 0.25%) on post-thawing ram sperm quality. In vitro tests, evaluating sperm motility and vigor, membrane and acrossome integrity and mitochondrial functionality were conducted before freezing and after thawing. Biochemical tests were performed to evaluate reactive oxygen species (ROS) and total antioxidant capacity (TOSC) by using a fluorometer and the fluorescent probe H2DCF-DA. The addition of xanthan did not benefit sperm membrane and acrossome integrity and mitochondrial functionality (p>0.05), but the post-thawing sperm motility was lower (p<0.05) in treatments with 0.20 and 0.25% xanthan (22.2% ± 4.1 and 20.8% ± 4.1, respectively) than in the control without xanthan (32.2% ± 4.1). On the other hand, xanthan showed antioxidant characteristics, since the concentration of ROS decreased with increasing xanthan production (p<0.05). Thus, xanthan showed extracellular antioxidant capacity, being efficient on reducting the ROS generated during the freezing process.