Effect of free range chicken egg yolk concentration to spermatozoa viability of koi fish (Cyprinus carpio, Linnaeus 1758) post-cryopreservation

Research on natural cryoprotectant such as chicken egg yolk, for sperm fish cryopreservation has already been done, however Using free range chicken egg yolk has yet to be done before in sperm fish, especially in koi fish. The aim of this research was to evaluate the effect of free range chicken egg yolk concentration on sperm viability of koi fish, Cyprinus carpio (Linnaeus, 1758) after freezing. Sperm was collected by hand stripping method, and diluted by a dilution solution (methanol 10 % and various concentrations of free range chicken egg yolk) with ratio 1:4. The given concentration of free range chicken egg yolk was 0 % (control), 5 %, 10 %, 15 %, 20 %, and 25 %. Freezing was done at -34 °C for 48 hours. The one factor ANOVA showed that various concentration of chicken egg yolk had effect (P < 0.05) on average value of viability of spermatozoa of koi fish 48 hours post-cryopreservation. Tukey's multiple comparison test showed significant differences (P < 0.05) between controls with other chicken egg yolk treatment. Free range chicken egg yolk at concentration 15 % is the optimum concentration in this study for maintaining viability of koi fish sperm 48 hours post-cryopreservation, because it produced the highest average value of percentage viability 84.5 ± 7.32 %.