Investigation of post-thaw quality and fertilization ability of carp (cyprinus carpio) sperm cryopreserved with extenders containing different avian egg yolk types

Egg yolk is one of the most widely used cryoprotective components of freezing extenders, especially for cryopreservation of mammalian species' sperm. However, there is lack of information regarding its efficacy on freezing of fish sperm. Thus, the objective of this experiment was to compare the effectiveness of egg yolk from diferent avian species (duck, goose and chicken) on post-thaw quality and fertlility of scaly carp (Cyprinus carpio) semen following cryopreservation. Sperm samples diluted (1:10) with the the sucrose-based extender were supplemented with 10, 15, 20% ratios of different avain egg yolks. In the control group, sperm samples were diluted with the sucrose-based extender, without egg yolk. Following dilution, sperm was equilibrated at 4°C for 10 min and aspirated into 0.25 mL straws, frozen 3 cm above of liquid nitrogen (LN2) surface for 10 min, and plunged directly into the liquid nitrogen (LN2). The spermatozoa were thawed in a water bath at 35°C for 30 s and fertilization was carried out using 1x105 spermatozoa/egg ratio. Based on the results, supplementation of sperm with duck egg yolk in sucrose-based extender improved post-thaw progressive motility (%), progressive motility duration (s), viability (%) and fertility (%) compared to the control group (p<0.05). The results showed that duck egg yolk could be used as an alternative instead of chicken egg yolk in sucrose-based extender for the cryopreservation of scaly carp sperm.