title: Effects of cryodevice type and donors' sexual maturity on vitrification of minke whale (Balaenoptera bonaerensis) oocytes at germinal vesicle stage.
abstract: Germinal-vesicle-stage oocytes enclosed with compact cumulus cell layers (COCs) were recovered from adult or prepubertal minke whale ovaries, and were vitrified in a solution containing 15% ethylene glycol, 15% DMSO and 0.5 M sucrose using either a Cryotop or an open-pulled straw (OPS) as the cryodevice. The post-warm COCs with normal morphology were cultured for 40 h in a 390 mosmol in vitro maturation medium, and oocytes extruding the first polar body were considered to be matured. The proportion of morphologically normal COCs after vitrification and warming was higher when the COCs were cryopreserved by Cryotop (adult origin, 88.4%; prepubertal origin, 80.8%) compared with the OPS (adult origin, 67.7%; prepubertal origin, 64.2%). The oocyte maturation rate was higher in the adult/Cryotop group (29.1%) compared with those of the prepubertal/Cryotop group (14.4%), the adult/OPS group (14.3%) and the prepubertal/OPS group (10.6%). These results indicate that the Cryotop is a better device than the OPS for vitrification of immature oocytes from adult minke whales.
authors.affiliation: Laboratory of Animal Reproduction, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwayama
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hochi
authors.forename: Megumi
authors.initials: M
authors.lastname: Kato
authors.forename: Masumi
authors.initials: M
authors.lastname: Hirabayashi
authors.forename: Masashige
authors.initials: M
authors.lastname: Kuwayama
authors.forename: Hajime
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohsumi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fukui
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D015925:Cryopreservation / Q000295:instrumentation* / Q000379:methods; D004121:Dimethyl Sulfoxide; D019855:Ethylene Glycol; D009865:Oocytes; D013395:Sucrose; D014907:Whales
chemical_list: D013395:Sucrose; D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide