Characterization and seminal cryopreservation of three species of birds of prey.

Background: Assisted reproduction techniques in birds have contributed to many species' conservation and sustainable use. One of these techniques is semen cryopreservation, which is possible following the discovery of suitable cryoprotectants. Aims: This study aimed to characterize the fresh and post-thaw ejaculates of different species of birds of prey. Methods: The following species were included in the study: red-tailed hawk (Buteo jamaicensis) n=3, golden eagle (Aquila chrysaetos) n=3, and Harris's hawk (Parabuteo unicinctus) n=3. Twenty-five ejaculates were obtained for each species. The percentage of spermatozoa motility, viability, and morphology were evaluated. Results: Evident differences were observed among the ejaculates of the three species, particularly in sperm length and between the fresh and post-thaw parameters of the same species in which the motility reduced to approximately 40% after thawing. It was demonstrated that sperm cryopreservation of the studied species was possible using the same freezing protocol. Conclusion: This study showed that sperm characteristics could influence the parameters obtained during their in vitro conservation, both in the fresh and post-thaw states.

Oviductal Proteins Effect in Rooster Spermatic Cryopreservation.

BACKGROUND: Cryopreservation induces spermatic cryo capacitation, which can decrease thawed sperm fertilizing capability. OBJECTIVE: To evaluate the effect of uterus-vaginal union protein factors to inhibit sperm cryo capacitation and maintain viability and fertilizing capability of rooster spermatozoa. MATERIALS AND METHODS: Rooster spermatozoa was cryopreserved using Lake extender supplemented with different hen's uterus-vaginal junction protein concentrations, to determine spermatic viability, sperm physiological condition and fertilizing capability in vivo. RESULTS: It was possible to induce spermatic decapacitation in vitro, inhibiting cryo capacitation and allowing fertility results comparable to those obtained with fresh semen. CONCLUSION: Uterus-vaginal protein extracts induce spermatic decapacitation in vitro.