title: Effect of group culture and embryo-culture conditioned medium on development of bovine embryos.
abstract: We investigated the effect of group culture on bovine embryo development, and also investigated the effect of embryo-culture conditioned medium on developmental competence of individually cultured bovine embryos. Slaughterhouse-derived bovine oocytes were matured and fertilized in vitro. The presumptive zygotes were cultured individually or cultured in groups of 2 to 5 embryos with a constant culture density (5 mul/embryo). After 7 days of culture, the rates of embryos developed to the blastocyst stage were significantly higher (P < 0.05) in group cultures of more than 3 embryos/drop than for embryo culture of 1 or 2 embryos/drop. These results suggest a beneficial effect of group culture may be exerted by possible growth promoting factors secreted by embryos. In the next experiment, we investigated the effect of timing of fresh medium replacement on the development of embryos cultured in groups. The blastocyst formation rate was lower when culture medium was replaced freshly on days 2-4 after fertilization than on days 5-6. The blastocyst formation rates of single-cultured embryos were significantly (p < 0.05) increased by the addition of conditioned medium derived from multiple-embryo culture. These results indicate that group culture promotes embryo development and that embryo culture-derived conditioned medium is effective for supporting development of single cultured embryos.
authors.affiliation: Livestock Research Institute of Oita Prefectural Agriculture, Forestry and Fisheries, Research Center, Kuju, Oita, Japan. fujita-tatsuo@pref.oita.lg.jp
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Fujita
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Umeki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shimura
authors.forename: Kouji
authors.initials: K
authors.lastname: Kugumiya
authors.forename: Kazuho
authors.initials: K
authors.lastname: Shiga
mesh_terms: D000818:Animals; D002417:Cattle; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D046149:Embryo Culture Techniques / Q000379:methods / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects*; D005307:Fertilization in Vitro / Q000662:veterinary; D013997:Time Factors
chemical_list: D017077:Culture Media, Conditioned