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Title: OOCYTE RECOVERY AND MATURATION IN THE AMERICAN BLACK BEAR (URSUS AMERICANUS): A MODEL FOR ENDANGERED URSIDS

Author
item JOHNSTON L A - HENRY DOORLY ZOO,OMAHA,NE
item Donoghue, Ann - Annie
item IGO W - WVA DEP NAT RESOUR,ELKINS
item SIMMONS L G - HENRY DOORLY ZOO,OMAHA,NE
item WILDT D E - NAT ZOO PK, SMITHSONIAN
item RIEFFENBERGER J - WVA DEP NAT RESOUR,ELKINS

Submitted to: Journal of Experimental Zoology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: A study was conducted to determine if meiotic maturation could be induced in oocytes of American Black bear as a model system for oocyte rescue techniques for endangered bear species. Ovaries were obtained from 48 black bears which yielded 2,403 oocytes of which 777 (32.2%) were morphologically classified as excellent quality. The highest incidence of metaphase II oocytes (those maturing in culture) was reached between 48 an 60 h of in vitro incubation, 26.4 % and 37.3%, respectively. These results demonstrate that bear oocytes undergo nuclear maturation in vitro and suggest that the black bear could be a useful model for developing oocyte rescue techniques for related, but endangered species

Technical Abstract: A study was conducted to determine if meiotic maturation could be induced in oocytes of American black bear as a model system for oocyte rescue techniques for endangered ursids. Ovaries were obtained from 48 black bears which yielded 2,403 oocytes of which 777 (32.2%) were classified as excellent quality. More total oocytes were recovered from donors that were eanestrous compared to luteal/pregnant at the time of ovarian excision. Delaying the recovery of oocytes from antral follicles within excised ovaries from 12-24 h or 25-36 h had no effect on the overall number of high quality oocytes recovered or subsequent maturational ability. The highest incidence of metaphase II oocytes was reached between 48 and 60 h of in vitro incubation, 26.4% and 37.3%, respectively. Donor status had no influence on the oocyte maturation rate by 24 or 48 h, but by 60 h, more oocytes recovered from anestrous females had achieved metaphase II compared dto luteal/pregnant counterparts. These results demonstrate that bear oocytes undergo nuclear maturation in vitro and suggest that the black bear could be a useful model for developing oocyte rescue techniques for related, but endangered species.