Cryoprotectant Effect of Pentoxifylline on Boar Spermatozoa Cryopreserved by the Liquid Nitrogen Vapor Method

The objective of this study was to investigate the influence of the addition of cryoprotectants to freezing extenders before semen cryopreservation on boar sperm quality as well as investigate their optimum concentrations. To evaluate the effect of pentoxifylline (0, 5, 10, 20 mM) added in egg yolk extender freezing medium on motion characteristics, motility, viability and acrosomal morphology of spermatozoa at post thawing of cryopreservation. Semen were collected from 12 boars and frozen on the same day. Qualified semen samples (motility>80%) from each boar were subdivided four groups, 0 (control), 5 mM (T1), 10 mM (T2) and 20 mM (T3). Motility was assessed for % motile cell characteristics using computer-assisted semen analysis (CASA; SAIS SI-100, Medical supply, Korea). Frozen sperms were thawed in Beltsville Thawing Solution (BTS) then incubated at 38℃ for 20 minutes. Progressive motility, average path velocity, straight line velocity, curvilinear velocity and total motility were higher (p<0.05) in 0 mM (control group) as compared with pentoxifylline treated group. Moreover, pentoxifylline addition did not damage acrosomal morphogenic effect of spermatozoa. Nevertheless, pentoxifylline concentration treatment did not affect the viability of the spermatozoa as the concentration increased. The data showed that pentoxifylline as an additive cryoprotectant was not able to improve sperm motility but also quality in cryopreservation.