Comparison of Cryoresistance of Testicular and Urinal Spermatozoa of the Toad Bufo bufo (Amphibia, Anura, Bufonidae) during Slow Freezing

A comparative study of the morphofunctional parameters of testicular (non-activated) and urinal (activated) spermatozoa of the common toad Bufo bufo (L., 1758) before and after cryopreservation was carried out. Cryopreservation was performed by a slow method. Sucrose (10%) and dimethylformamide (12%) were used as cryoprotectants. It was shown that the pool of testicular spermatozoa contains significantly more cells with abnormal morphology both before and after cryopreservation. The osmoticity of the base medium for the cryoprotective solution (Ringer's solution for amphibians - 230 mOsm or urinal plasma - 45 mOsm) had little effect on the survival of testicular and urinal spermatozoa during cryopreservation. Comparison of the morphological and functional characteristics of spermatozoa before and after freezing-thawing indicates that the cryoresistances of testicular and urinal spermatozoa differ slightly.