Cryopreservation of common carp (Cyprinus carpio) embryos using different cryoprotectant

This study reports that common carp (Cyprinus carpio) embryos were successfully frozen and preserved by vitrification. The modified Haga solution was tested by using two different cryoprotectants and three different concentrations at 4°C to obtain appropriate vitrified solutions ((dimethylsulfoxide 5, 10, 15% (DMSO) and glycerol 5, 10, 15% (gly)) in the study.  The hatching rates of embryos exposed to cryoprotectants were also evaluated. The results showed that when 2-hour stage embryos were incubated with 10 and 15% DMSO levels, no hatching was observed, while 36% rate was obtained in the 5% DMSO group. The percentage of embryos was incubated in Hank's solution (HBSS) showed a highly significant difference (p<0.05) compared to those were incubated in the hatchery water (Hw). The hatching rate of embryos was incubated in HBSS with 5% gly  also showed a highly significant difference (p<0.05) than those embryos were incubated in Hw only, Hw with 5% gly, 10% gly and 15% gly and those incubated in HBSS with 15% gly. For the cryopreservation results of 49-h stage carp embryos, four embryos (8%) were recovered from 100 frozen embryos after thawing of 49-h stage embryos using extender (Haga solution) in LN2 (liquid nitrogen). At the end of the study, it was revealed that DMSO with the concenteration 10% - 15% showed lethal effect on carp embryos. The study suggests that cryopreservation of carp embryos is possible and the results showed that the best cryoprotectant which was used for cryopreservation is 5% DMSO. The results of this investigation establish that cryopreservation of carp embryos is possible by vitrification. However, more studies are needed in the future to increase the carp embryos survival rate.