Effect of Antibiotics Metranidazole, Streptomycin, and Gentamicin on the Maintenance of Sperm Motility of the European Common Frog (Rana temporaria) During Refrigerated Storage

The problem of asynchrony in the production of gametes in amphibians can be solved by increasing the longevity of spermatozoa during the storage of spermic urine with antibiotics. This study evaluated the effect of metranidazole and streptomycin at concentrations of 0.1, 0.2, 0.4, and 1 mg/ml on the maintenance of motility and the longevity of spermatozoa in the spermic urine of the European common frog (Rana temporaria) during refrigerated storage at 4°C. Metranidazole did not improve the lifespan of spermatozoa, and streptomycin had a positive effect at all analyzed concentrations. In addition, the streptomycin and gentamicin at the same concentrations of 0.05, 0.1, and 0.2 mg/ml were compared for their effect on maintaining sperm motility during storage. In spermic urine samples with significant bacterial contamination, no significant differences were found in the effect of streptomycin and gentamicin on sperm motility. In the absence of any visible signs of significant bacterial contamination of spermic urine samples, the motility of spermatozoa with gentamicin remained significantly longer than that with streptomycin for all analyzed concentrations. In addition, in this study, for the first time, a positive correlation was revealed between the initial concentration of spermatozoa and the longevity of spermatozoa during the refrigerated storage of amphibian spermic urine samples with antibiotics (r = 0.899, P 0.0001). However, no relationship was found between the longevity of spermatozoa and the initial osmolality of spermic urine in the range from 62 to 92 mosmol/kg (r = 0.083, P = 0.768).