Prognostic value of canine frozen-thawed semen parameters on in vitro sperm-oocyte interactions.
Combining the data from conventional semen analysis with oocyte penetration assays should improve the assessment of the fertilizing ability of a semen sample. Thus, the objective of the present study was to evaluate the prognostic value of various semen parameters on the in vitro interactions between frozen-thawed canine sperm and homologous oocytes. Ten ejaculates from five stud dogs (two ejaculates/dog) were collected by digital manipulation. Semen samples were evaluated, extended in Tris-egg yolk-glycerol, frozen and stored in liquid nitrogen, and thawed several weeks later. Samples were evaluated for motility and sperm populations by computer-aided semen analysis (CASA), plasma membrane integrity (carboxy-fluorescein diacetate and propidium iodide), and sperm morphology (Bengal Rose). Thawed spermatozoa were also incubated with homologous oocytes for 18 h in an atmosphere of 5% CO(2) and 95% air at 38 degrees C and sperm-oocyte interactions were evaluated. Simple linear regression models were calculated, with sperm parameters as independent variables and sperm-oocyte interactions as the dependent variable. There were significant associations between: percentage of oocytes bound to spermatozoa and beat cross frequency (BCF; R(2)=63%); percentage of oocytes that interacted with spermatozoa and BCF (R(2)=73%); and number of penetrated spermatozoa and velocity average pathway (VAP; R(2)=64%) and velocity straight line (VSL; R(2)=64%). Although plasma membrane integrity and sperm morphology had little prognostic value for in vitro interactions between canine frozen-thawed sperm and homologous oocytes, some motility patterns (evaluated by CASA) were predictive of in vitro sperm-oocyte interactions.
Silva
Alexandre R
AR
Laboratory of Carnivore Reproduction-FAVET, UECE, Paranjana Ave. 1700, Itaperi 60740-000, Fortaleza, Ceará, Brazil. legio2000@yahoo.com
Cardoso
Rita de Cássia S
Rde C
Silva
Lúcia D M
LD
Chirinéa
Viviane H
VH
Lopes
Maria D
MD
Souza
Fabiana F
FF
D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D004285:Dogs / Q000502:physiology*; D004542:Ejaculation; D005260:Female; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008297:Male; D009865:Oocytes / Q000502:physiology; D011237:Predictive Value of Tests; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013075:Sperm Capacitation / Q000502:physiology; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*