title: Effects of maturation and co-culture treatments on the developmental capacity of early bovine embryos.
abstract: A total of 901 cumulus-oocyte complexes (COCs) were collected from bovine ovaries obtained at a local abattoir. COCs randomly assigned to Treatment I (n = 451), were cultured in TCM-199 + 10% fetal bovine serum (FBS) and hormones, while oocytes in Treatment II (n = 450) were cultured in TCM-199 + 20% estrous cow serum (ECS). Assessment of maturation revealed that 91.3% (42/46) of oocytes in Treatment I had reached metaphase II of meiosis, which was greater (P less than 0.05) than the 73.3% (33/45) in Treatment II. Following in vitro fertilization, 203 oocytes from Treatment I were co-cultured on bovine granulosa cells (Treatment IA) while the remaining 202 oocytes were co-cultured on bovine oviductal cells (Treatment IB). Similarly, 203 oocytes from Treatment II were co-cultured on granulosa cells (Treatment IIA) or oviductal cells (Treatment IIB, n = 202). Co-culture was maintained for 8 days. The proportion of cleaved zygotes was higher (P less than 0.05) in Treatment IB (86.6%) compared to Treatments IA (78.8%), IIA (58.1%), and IIB (64.8%). The proportion of cleaved zygotes that progressed beyond the 16-cell stage was also greater (P less than 0.001) in Treatment IB (71.4%) compared to Treatments IA (50.0%), IIA (35.4%) and IIB (55.8%). Treatment IB also produced the highest proportion of blastocysts (P less than 0.0001) (41.1%) versus 24.6% (IA), 11.3% (IIA) and 18.3% (IIB). The proportion of day 6 morulae that progressed to form day 8 blastocysts was similar for both co-culture treatments (IA, 70.1%; IB 70.2%; IIA, 51.5%; IIB 50.8%) and varied only between in vitro maturation groups.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Alta Genetics, Calgary, Alberta, Canada.
authors.forename: K E
authors.initials: KE
authors.lastname: Wiemer
authors.forename: A J
authors.initials: AJ
authors.lastname: Watson
authors.forename: V
authors.initials: V
authors.lastname: Polanski
authors.forename: A I
authors.initials: AI
authors.lastname: McKenna
authors.forename: G H
authors.initials: GH
authors.lastname: Fick
authors.forename: G A
authors.initials: GA
authors.lastname: Schultz
mesh_terms: D000818:Animals; D002417:Cattle; D002455:Cell Division; D002469:Cell Separation; D002478:Cells, Cultured; D046508:Culture Techniques / Q000379:methods*; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development; D005187:Fallopian Tubes / Q000166:cytology; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins; D006107:Granulosa Cells / Q000166:cytology; D009865:Oocytes / Q000166:cytology; D013256:Steroids; D013997:Time Factors
chemical_list: D006062:Gonadotropins; D013256:Steroids