Cryopreservation of coporo (Prochilodus mariae) milt using three permeating cryoprotectant agents and two freezing systems

In the present study, we examined three permeating cryoprotectant agents (CPAs) and two freezing systems for the cryopreservation of coporo spermatozoa. Milt samples of 5 males were diluted with cryoprotectant solutions containing 10% Me2SO, 10% MeOH and 8% DMA, respectively, with or without hen egg yolk. Half of the 0.25-ml straws were frozen in a programmable system and the other half in a dry shipper. Sperm motility and viability were evaluated in both fresh and post-thaw samples by conventional methods. Sperm motility and viability were both significantly lower in all post-thaw treatments. Of the CPA tested, 10% MeOH provided the best protection as there were no significant differences in motility (66.67 +/- 5.77% vs. 66.68 +/- 5.70%) and viability (80.00 +/- 4.35% vs. 83.33 +/- 0.57) between the programmable system and the dry shipper when that CPA was used. On the other hand, the most effective freezing system was the programmable freezer as all the CPA tested presented sperm motility (43.33 +/- 5.77 to 66.50 +/- 5.00%). In conclusion, coporo sperm can be cryopreserved in either of these two systems using 10% methanol.