title: Comparative studies on lipid analysis and ultrastructure in porcine and southern minke whale (Balaenoptera bonaerensis) oocytes.
abstract: The present study was conducted to clarify the difference in the color of the cytoplasm in immature follicular oocytes from prepubertal and adult minke whales. The four lipid contents (triglyceride, total cholesterol, phospholipids and non-esterified fatty acids) in vitrified immature oocytes from prepubertal and adult minke whales, and also in fresh and vitrified immature porcine oocytes, were measured. The lipid contents in vitrified-warmed minke whale oocytes were similarly high compared with those in vitrified-warmed porcine oocytes. In particular, the total cholesterol and phospholipid contents in the vitrified immature oocytes from prepubertal and adult minke whales were significantly (P<0.05) higher than those from prepubertal pigs. Furthermore, the distribution of lipid droplets in fresh and vitrified immature oocytes was observed in transmission electron microscopy. Lipid droplets in the prepubertal minke whale oocytes were distributed throughout the cytoplasm. In contrast, adult minke whales had larger lipid droplets which were distributed mainly in the central portion of the cytoplasm. The lipid droplets of immature oocytes from prepubertal pigs were larger than those in minke whale oocytes. These results indicated that the difference in the distribution of the cytoplasmic lipid droplets may result in the difference in the color tone of both prepubertal and adult whale oocyte cytoplasm.
authors.affiliation: Laboratory of Animal Reproduction, Obihiro University of Agriculture and Veterinary Medicine, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Fujihira
authors.forename: Mikio
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Motoki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Masao
authors.initials: M
authors.lastname: Ohnishi
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: D000818:Animals; D005615:Freezing; D050356:Lipid Metabolism; D046529:Microscopy, Electron, Transmission; D009865:Oocytes / Q000378:metabolism* / Q000648:ultrastructure; D012741:Sexual Maturation / Q000502:physiology*; D013552:Swine; D014907:Whales