title: Development and quality of sheep embryos cultured in commercial G1.3/G2.3 sequential media.
abstract: Present study assesses the developmental ability and quality of ovine IVP embryos derived from culture in sequential media G1.3/G2.3. A total of 1474 cumulus-oocyte complexes were matured in M199 supplemented with EGF and FCS for 24h in 5% CO2 in humidified air at 39 degrees C. Oocytes were co-incubated in SOF medium with 1 x 10(6) spermatozoa/ml at the same temperature and gas conditions (Day 0 p.i.). Presumptive zygotes at 20 h p.i. were denuded, washed and placed in culture in SOF (control; n=742) or G1.3 media supplemented with 3mg/ml of BSA (n=732) under mineral oil in a humidified and controlled atmosphere at 39 degrees C. Embryos in the treated group were changed to G2.3 medium on Day 3 of culture. A group of blastocysts in each group were frozen by conventional method (SOF, n=55; G1.3/G2.3, n=48). In vivo embryos (n=72) were recovered at Day 7 from the uterus of progestagen+eCG treated females and they were cultured in defined medium (n=38) or frozen (n=34) directly after recovery. Cleavage rate of IVP embryos recorded at 48 h p.i. was similar for control and treated embryos (49.8 versus 47.5%). There were no significant differences in blastocyst development from the two groups on Day 6 (26.0 versus 25.6%), 7 (42.1 versus 38.6%) or 8 (50.8 versus 43.2%). Blastocyst development rates from total oocytes cultured were comparable (24.1 versus 21.5%). However, the proportion of hatched blastocysts was significantly higher for control embryos (86.6 versus 44.3%, P<0.0001). In addition, embryos cultured in SOF had higher re-expansion rates post-thawing at 24h (38.2 versus 6.2%), 48 h (36.4 versus 4.1%) and 72 h (34.5 versus 4.1%) and hatching rate (32.8 versus 2.0%) than embryos cultured in sequential media (P<0.0001). In vivo embryos showed higher hatching rate (61.7%) than IVP groups (SOF, P<0.01; G1.3/G2.3, P<0.0001) but lower than their fresh cultured counterparts (86.8%; P=0.01). In conclusion, G1.3/G2.3 media supported high developmental rates of embryos in vitro but the quality of the embryos was impaired.
authors.affiliation: Dpto. de Ciencia y Tecnología Agroforestal, Escuela de Ingenieros Técnicos Agrícolas, Universidad de Castilla La Mancha, C/Ronda Calatrava, 7 13071-Ciudad Real, Spain. rosa.garcia@vet.ucm.es
authors.forename: R M
authors.initials: RM
authors.lastname: Garcia-Garcia
authors.forename: F
authors.initials: F
authors.lastname: Ward
authors.forename: S
authors.initials: S
authors.lastname: Fair
authors.forename: C M
authors.initials: CM
authors.lastname: O'Meara
authors.forename: M
authors.initials: M
authors.lastname: Wade
authors.forename: P
authors.initials: P
authors.lastname: Duffy
authors.forename: P
authors.initials: P
authors.lastname: Lonergan
mesh_terms: D000818:Animals; D003470:Culture Media; D046149:Embryo Culture Techniques / Q000662:veterinary*; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D008297:Male; D012756:Sheep / Q000196:embryology*
chemical_list: D003470:Culture Media