It has been evaluated, in a coculture system without continuous CO2 flow, the possibility to enhance the percentage of blastocists obtained from two cells mouse embryos by partial (30%) replacement (each 24, 48 and 72 hours of intervals) of two culture media (TCM 199/NaHCO3 and TCM 199/25 mM HEPES). The embryos, randomiy allocated in closed cultures tubes with 2 ml of medium and bovine oviduct monolayer, were maintained at 37°C during 96 hours. No diferences between spreaded blastocists were verifica when the media were replaced at ali intervals, however, the medium TCM 199/25mM HEPES was significantiy more effective (P £ 0.01) then TCM 199/NaHCO3.
coculture; culture medium; embryo
