title: Effects of the estrous cycle on the efficacy of oocyte collection and in vitro embryo production in Duroc-breed.
abstract: Collection efficacy and in vitro embryo developmental ability of oocytes obtained from Duroc-breed ovary donors at different stages of the estrous cycle (days 6, 12 and 16 after estrus) were performed. The numbers of collected oocytes did not differ significantly among the different estrous cycle groups (total 72-90 oocytes per gilt). However, the blastocyst rates of oocytes collected on days 12 and 16 (9.2% and 19.4%, respectively) were significantly higher than those on day 6 (1.1%). More oocytes were obtained on day 16 from small follicles (<2 mm in diameter; 85.3 oocytes per gilt) than from medium-sized (≥2-<6 mm) and large (≥6 mm) follicles (17.5 and 12.8 oocytes, respectively). The blastocyst rates in both the medium-sized and large follicle groups (20.0% and 19.2%, respectively) were significantly higher than that in the small follicle group (6.3%). The blastocyst cell numbers in both the medium-sized and large follicle groups (39.4 and 43.3 cells, respectively) were significantly higher than that in the small follicle group (30.6 cells). The results suggest that oocyte collection from cycling Duroc pigs can be carried out efficiently from the late luteal to follicular stage. Those oocytes collected from medium-sized and large follicles show better embryo development.
authors.affiliation: Department of Technology, National Livestock Breeding Center, Fukushima.
authors.forename: Koji
authors.initials: K
authors.lastname: Misumi
authors.forename: Yuri
authors.initials: Y
authors.lastname: Hirayama
authors.forename: Misae
authors.initials: M
authors.lastname: Suzuki
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakai
authors.forename: Junko
authors.initials: J
authors.lastname: Noguchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaneko
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kikuchi
mesh_terms: D000818:Animals; D001755:Blastocyst; D002452:Cell Count; D004622:Embryo, Mammalian / Q000196:embryology*; D047108:Embryonic Development; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D008183:Luteal Phase / Q000502:physiology; D054315:Oocyte Retrieval / Q000379:methods*; D009865:Oocytes / Q000254:growth & development*; D006080:Ovarian Follicle / Q000166:cytology; D013552:Swine; D013997:Time Factors
keywords: follicle development; in vitro embryo production; oocyte collection; pig; pure breed