Oxidative stress on alpaca epididimal sperm frozen with different concentrations of seminal plasma

Objective. To assess the oxidative stress on alpaca epididimal sperm frozen with different concentration of seminal plasma. Materials and methods. 29 post mortem alpaca epididymis were used. Epididymal sperm were obteined thought cuts and suspended in a diluent based on skim milk, egg yolk and fructose and dimethylacetamine. Samples were separated into four aliquots which were supplied with seminal plasma (v/v) in concentrations of 0, 10, 25 and 50% respectively; then, sperm motility was assessed before freezing; then, motility was assessed before freezing with an automatic freezer machine. After thawing, mitochondrial membrane activity, sperm viability, lipid peroxidation and sperm apoptosis were assessed using flow cytometry with images. Results. Sperm exposed to 50% seminal plasma showed the lowest post-thaw motility (3.5±3.7%) and the highest percentages of apoptotic cells (71.43±20.6%). No significant differences were found in the rest of parameters. Conclusions. This study constitutes non-conclusive evidence that presence of seminal plasma does not affect viability, mitochondrial activity, or lipid peroxidation of alpaca epididymal sperm during cryopreservation processes; however, when it is absent or added up to 25% in the cryopreservation process, it may be possible to obtain better results in terms of sperm motility and sperm apoptosis.