The goal of this study was to investigate the effect of different concentrations of pentoxifylline (PTX) on frozen-thawed goat spermatozoa. Semen was collected from four mature goats (3-4 years, 55-65) by electroejaculation. Only semen samples with motility more than 70% and sperm concentration more than 3×107sperm/ml were pooled and used for cryopreservation. The pooled samples were then divided into four equal parts, diluted with Tris-based extender containing different concentrations of PTX (0, 3, 6, 9 mM), filled in 0.25-ml French straws, and then frozen 4 cm above nitrogen vapor after cooling to 5˚C in 2.5 h. The frozen spermatozoa were thawed at 37°C for 30 sec. The thawed semen samples have been evaluated for total motility and progressive motility by CASA, and viability using eosin-nigrosine staining method. The results showed that the treatments supplemented with PTX indicate significantly (P<0.05) an increase in progressive motility compared to control. Moreover, the observed data enhanced significantly (P<0.05) total motility and viability when extenders contained 3 and 6 mM PTX, compered to control and diluent added 9 mM PTX. However, regarding total motility and viability, the results of control and diluent contained 9 mM PTX present significantly (P>0.05) no differences. Subsequently, comparing the diluents supplemented with 3 concentrations of PTX demonstrated that 3 mM was the best extender, and presented the most beneficial effect on frozen-thawed goat spermatozoa. Therefore, we suggest using this concentration for freezing of goat spermatozoa, however, further studies seem to be necessary to confirm present findings.
