Successful Culture In Vitro of Swine Embryos to the Blastocyst Stage2

One hundred and twenty-three porcine embryos between the two-cell and morula stage of development were collected from 24 gilts. Embryos were placed randomly into culture among three media and two gaseous atmospheres and development was recorded at 24-hr intervals for the duration of culture. The number of cells present at the cessation of culture was determined following aceto-orcein staining. Development of embryos in vitro was measured by a cleavage index based on the number of cells present at the cessation of culture. Significant differences were found among the culture media and gaseous atmospheres with a significant (P<.02) media × gaseous atmosphere interaction. Embryos in Whitten's medium (WM) with 1 mg/ml bovine serum albumin (BSA), WM with 15 mg/ml (BSA) or Modified Ham's F-10 (MHF-10) all cultured under a 5% C02 in air atmosphere had cleavage indices of .69, 1.00 and .53, respectively. Embryos in WM with 1 mg/ml BSA, WM with 15 mg/ml BSA, or MHF-10 all cultured under a reduced gaseous atmosphere of 90% N2, 5% CO2 and 5% O2, had cleavage indices of 1.43, 1.93 and .71, respectively. The stages of development at the time of initiation of culture influenced (P<.001) the degree to which the embryos ultimately developed when development was measured by a cleavage index. Five-to seven-cell (2/23), eight to 12-cell (6/28), andmorulae (19/20) developed into blastocysts with one to two-cell and three to four-cell embryos failing to develop past the morula stage.