Sequential culture medium promotes the in vitro development of Macaca fascicularis embryos to blastocysts.

In vitro production of blastocyst stage embryos from Macaca fascicularis (Mf) has not previously been demonstrated without cell support. Historical data indicates that a large proportion of Mf embryos arrest at the morula stage in nonsequential culture medium (NSM) lacking serum supplementation and/or cell support. Here we report the application of a sequential culture system supporting in vitro production of Mf blastocysts. Mf embryos produced by in vitro fertilization (IVF; n = 69) were subjected to in vitro culture without cell support in either a commercial sequential embryo culture medium (SM) or an NSM. At 24 hr post-insemination (PI) embryos generated from in vivo and in vitro matured oocytes and cultured in the NSM cleaved to two or more cells in significantly greater proportions (15/23; 65%) compared to embryos cultured in SM (14/46; 30%). However, by day 3 PI embryo development beyond eight cells was not different in NSM (9/23; 39%) compared to SM (25/46; 54%). At day 5 PI embryo development to the morula stage was slightly lower in NSM (8/23, 35%) compared to SM (21/46, 45%), and embryo degeneration was slightly higher in NSM (9/23, 39%) compared to SM (9/46, 20%). After 7-9 days of in vitro culture, embryo development to the blastocyst stage and embryo degeneration were significantly lower and higher, respectively, in NSM (0/23, 0%; and 23/23, 100%) compared to SM (9/46, 20%; and 26/46, 56%). In this study the sequential culture system was better able to support in vitro development of Mf embryos compared to nonsequential culture systems.