NONSPECIES-SPECIFIC EFFECTS OF MOUSE OVIDUCTS ON THE DEVELOPMENT OF BOVINE IVM IVF EMBRYOS BY A SERUM-FREE COCULTURE/

In Experiment 1, development of bovine embryos derived from in vitro-m atured (IVM) and in vitro-fertilized (IVF) oocytes was examined under 4 culture conditions: 1) co-culture with mouse ampullae continuously f or 8 d, 2) co-culture with mouse ampullae that were replaced with fres h ampullae at 48-h intervals, 3) co-culture with bovine granulosa cell monolayers, and 4) culture in medium alone. Culture medium consisted of tissue culture medium 199 (TCM-199) supplemented with 1% fetal calf serum (FCS). Inseminated oocytes were transferred to each of the cult ure treatment 24 h after insemination and were cultured for 8 d. The n umber of blastocysts per number of cleaved ova obtained after co-cultu re with mouse ampullae (42.9%) was significantly (P<0.05) higher than that obtained after co-culture with granulosa cell monolayers (28.3%) or culture without cells (4.2%). In Experiment 2, the developmental ab ility of bovine IVM/IVF embryos co-cultured with mouse ampullae supple mented with or without serum was examined. When serum was excluded fro m the culture medium, 26.4% (33/125) of the total number of embryos cu ltured were able to develop to the blastocysts stage using this co-cul ture system. This value was comparable to that obtained in a serum-sup plemented co-culture system (30.7%; 39/125). In addition, the developm ental ability of embryos that reached to the 4-cell stage or beyond at 46 to 48 h after insemination was not significantly different when th e embryos were co-cultured with mouse ampullae with (38.5 vs 44.6%) or without (37.0 vs 33.8%) serum.