Cryopreservation of sperm in annual fish Austrolebias minuano (Cyprinodontiformes; Rivulidae)

The effects of the cryoprotectants dimethyl sulfoxide, glycerol and methyl glycol at different concentrations on Austrolebias minuano sperm quality parameters were evaluated in this study. The cellular kinetic parameters, determined using flow cytometry, indicated the best results with the samples cryopreserved with 7.5% methyl glycol. Dimethyl sulfoxide concentrations of 7.5% and glycerol concentrations of 10%, 12.5% and 15% demonstrated the least benefit across all evaluated sperm kinetic parameters. When assessed using flow cytometry, a concentration of 7.5% methyl glycol similarly showed better sperm kinetic parameters than 12.5% dimethyl sulfoxide. We conclude that cryoprotectants, especially methyl glycol, are effective for the preservation of sperm quality in A. minuano. However, high sensitivity of spermatozoa against glycerol was observed in these studies; thus, it is not recommended for cryopreservation purposes.