In vitroeffect of various cryoprotectants on the semen quality of endangered Oravka chicken

Abstract

SummaryWe aimed to compare the effect of three different permeating cryoprotectants on the post-thaw spermatozoa quality. Pooled semen from Oravka cock line (n= 6) was diluted inKobidil+extender and frozen in cryoprotectant solutions containing 8% dimethylsulfoxide (DMSO), 8% ethylene glycol (EG) or 8% glycerol (GL) in liquid nitrogen vapours before being plunged into the liquid nitrogen. Spermatozoa motility parameters were assessedin vitroafter freezing–thawing by a computer-assisted semen analysis (CASA) system and viability status was examined using fluorescent probes. The lower percentage (P <0.05) of motile and progressively moving spermatozoa immediately after thawing were obtained in all experimental groups (DMSO, EG, GL) compared with the control. Significant (P< 0.05) differences in total motility and progressive movement between GL and DMSO, EG groups were observed. However, the higher number (P <0.05) of acrosome damaged spermatozoa was found in the DMSO and EG groups and no significant differences were observed in the GL group compared with the control. Differences (P< 0.05) between experimental groups and the control in the results of spermatozoa necrosis were observed. No significant differences in the percentage of apoptotic spermatozoa were found between control and experimental groups. However, significant differences (P< 0.05) in number of live and necrotic spermatozoa between GL and DMSO, EG groups were examined. The findings of the present study indicate that glycerol seems to be suitable for semen cryopreservation in the gene banks. In addition, fertility evaluationin vivois needed in order to evaluate the possible contribution for the bank of animal genetic resources.