title: Effect of serum-free co-culture and synchrony of recipients on development of cultured sheep embryos to fetuses.
abstract: The percentage of sheep embryos that continued to develop after collection and immediate transfer on d 2 after estrus was similar when phosphate-buffered saline with 10% fetal calf serum (PBSFCS, 45%), physiological saline (50%), or tissue culture medium 199 supplemented with 10% fetal calf serum (M199FCS, 47%) was used to flush embryos from oviducts. Co-culture of sheep embryos for 3 d with oviductal cells tended (P = .1) to reduce the percentage of embryos that developed to fetuses after transfer compared with those embryos transferred immediately. Tissue culture medium 199 supplemented with .3% BSA (M199BSA) was an adequate substitute for M199FCS for culture of sheep oviductal cells if tissue culture wells were pretreated with fibronectin. Estradiol in concentrations from 10 to 1,000 pg/ml and progesterone at concentrations of 1 or 10 ng/ml in M199BSA failed to stimulate embryo development during 3 d of co-culture beyond that seen in co-culture with M199FCS or M199BSA without added steroid. Transfer of sheep embyros co-cultured for 3 d in M199BSA or M199FCS to recipients synchronized with donors resulted in about 19% of the embryos developing to fetuses, whereas transfer to recipients that were in estrus 24 h after donors resulted in 33% of embryos developing to fetuses. The significant (P less than .05) improvement for delayed recipients may reflect the relatively lesser developmental rate of co-cultured embryos compared with that of embryos in vivo. Embryo development into fetuses was similar after co-culture in M199FCS or M199BSA co-cultures; therefore, serum is not required for the co-culture of sheep embryos.
authors.affiliation: Beltsville Agric. Res. Center, U.S. Department of Agriculture, Beltsville, MD 20705.
authors.forename: C E
authors.initials: CE
authors.lastname: Rexroad
authors.forename: A M
authors.initials: AM
authors.lastname: Powell
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D003470:Culture Media; D004624:Embryo Transfer / Q000662:veterinary*; D005314:Embryonic and Fetal Development; D004958:Estradiol; D004973:Estrus Synchronization; D005260:Female; D005353:Fibronectins; D011374:Progesterone; D012756:Sheep / Q000196:embryology*
chemical_list: D003470:Culture Media; D005353:Fibronectins; D011374:Progesterone; D004958:Estradiol