Veterinarija ir Zootechnika

Abstract. Our study was aimed to evaluate the effect of vitrification on canine sperm parameters using a coconut water extender with an addition of egg yolk as a cryoprotectant. Semen collection was done separately by manual stimulation from twelve healthy adult dogs. Only the second fraction of the ejaculate was used in this study, which was evaluated for volume, concentration, vitality, total and progressive motility, kinetic parameters and morphology. Semen was diluted with a coconut water extender (50% (v/v) coconut water, 25% (v/v) distilled water and 25% (v/v) 5% anhydrous monosodium citrate solution) with an addition of 20% (v/v) egg yolk and fructose at 1% until final concentration of 100  106 spermatozoa/mL. After equilibration at 5ºC for 60 minutes, semen was vitrified by the “direct dropping method” into liquid nitrogen in spheres with a volume of 30 μL. After a week of storage, the spheres were warmed as three of them were dropped into 0.5 mL of CaniPlus AI (Minitüb, Germany) at 42ºC for 2 minutes and evaluated about the same parameters. The results showed that vitrification produced a statistically lower percentage of vital sperms, normal morphology and total motility (P < 0.05), but progressive motility and most of velocity parameters (VCL, VSL, VAP, LIN, ALH and BCF) did not differ (P > 0.05) compared to fresh semen samples. In conclusion, our results demonstrate that vitrification with a coconut water extender with an addition of 20% egg yolk as a cryoprotectant affects the quality of canine sperms, but may be useful as a successful alternative to conventional cryopreservation. Further research on the spermatozoa vitrification technique on enhancement in cooling and warming should be conducted and investigated.