Recovery rate, morphological quality and nuclear maturity of canine cumulus-oocyte complexes collected from anestrous or diestrous bitches of different ages.
Canine cumulus-oocyte complexes (COC) were recovered from ovaries of post-pubertal animals (1-3, 4-6 and 7-10 years old) at different ovarian estrous phases (anestrus and diestrus). The number of COCs, and the number and nuclear maturity of high-quality (grade-1) oocytes were assessed. For all animals, no significant differences were found between the two reproductive phases relatively to the total number of COCs and grade-1 oocytes recovered. However, significant higher numbers of COCs were recovered from young than from elderly animals, and the proportion of grade-1 oocytes was also significantly higher in the younger group than in the other two age-groups. Of 226 grade-1 oocytes, 73% were at the germinal vesicle stage (GV), 10% had resumed meiosis (9% at germinal vesicle breakdown; 1% at metaphase-I) and 17% were degenerated. A significant effect of the reproductive phase on oocyte nuclear maturity was found only for adult animals, with a higher number of GV oocytes being found at anestrous (79%) due to higher rates of meiosis resumption (34%) at diestrous. The high number of grade-1 oocytes with meiosis resumption and fragmented or unidentified nuclear contents, indicates that current criteria for the selection of viable canine COCs are not optimized and need a new definition.
Lopes
G
G
Department of Veterinary Clinics, Center for the Study of Animal Sciences (CECA), ICBAS, University of Porto, Lg Prof Abel Salazar, 2, 4099-003 Porto, Portugal.
Sousa
M
M
Luvoni
G Cecilia
GC
Rocha
A
A
D000367:Age Factors; D000780:Anestrus / Q000502:physiology*; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics / Q000502:physiology; D053938:DNA Fragmentation; D004031:Diestrus / Q000502:physiology*; D004285:Dogs; D005260:Female; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics / Q000502:physiology; D006080:Ovarian Follicle / Q000166:cytology; D020858:Tissue and Organ Harvesting / Q000379:methods*