| Popis: |
A heterologous bovine in vitro fertilization (IVF) system was used to study the functional competence of scimitar-horned oryx spermatozoa after cryopreservation. Four sperm-freezing methods were compared after dilution of ejaculates from six oryx with an equine semen extender: 1) dry ice, 2) dry shipper one-step, 3) dry shipper two-step, and 4) liquid nitrogen vapor. Post-thaw sperm motility, longevity, and acrosomal status were assessed and zona pellucida penetration, fertilization, and embryo cleavage were evaluated after coincubation of thawed oryx spermatozoa with in vitro-matured domestic cow oocytes. Sperm motility index (SMI) decreased (p0.05) over a 6-h period, but a high percentage (/= 65%) of spermatozoa contained intact acrosomes in all treatments. Despite differences in sperm motility among methods, oocyte penetration, fertilization, and embryo cleavage did not differ (p/= 0.05). However, cleavage success was50% across all treatments. There were positive correlations (p0.05; r = 0.81-0.97) between sample SMI at 3 and 6 h and fertilization, penetration, and cleavage, but no correlations (p/= 0.05) between SMI at 0 or 1 h and IVF success. This study demonstrates that compatible heterologous gamete interaction allows thorough assessment of post-thaw sperm function in an endangered antelope. Scimitar-horned oryx spermatozoa appear relatively tolerant of varied cryopreservation methods, and preserved samples exhibit adequate post-thaw function to warrant use for assisted reproduction. |
