Quantity and quality of oocytes recovered from donor bitches of different ages

In vitro studies that use isolated oocytes benefit from the ability to harvest oocytes of excellent morphological quality in sufficient numbers to allow the replicability of techniques and experiments. The objective of the present study was to verify the effect of the age of the donor bitch on the quantity and quality of oocytes recovered from isolated ovaries, using the slicing technique. Ten bitches (45 days to 13 years) were ovariohysterectomized, and the ovaries were placed in phosphate buffered saline (PBS), supplemented with bovine fetal serum (5%), and oocyte-cumulus-complexes (OCCs) were obtained by slicing the ovarian tissue. The OCSs were classified morphologically as Degree I (DI, best), Degree II (DII) and degenerated. A total of 427 oocytes were acquired, including 81, 109 and 237 that were graded as DI, DII and degenerated, respectively. Slicing yielded no OCS from animals < 2 months of age. In senile (> 9 years) bitches, bitches, there were more oocytes per bitch, compared to adult (2-6.5 years) bitches, but fewer DI oocytes, and more DII and degenerate oocytes. We inferred that using donors that were post-pubertal but not senile, would assure the recovery of high-quality oocytes by the slicing method. Additional studies are required to assess the quality of oocytes collected from pre-pubertal versus post-pubertal bitches < 2 years of age.