71 Bovine embryonic development observed by time-lapse system

The evaluation, in real time, of the kinetics of development is increasingly common in human IVF. Assessment of early embryonic development in bovine by time-lapse microscopy could be an indicator for the quality of subsequent blastocysts. Identification of key time points in early development can be used to predict the development potential of embryos and aid in the selection of transferred embryos to improve pregnancy rates. The EmbryoScope (VitroLife) time-lapse system allows for the visualisation of early embryonic development from the zygote to the blastocyst stage. Using the EmbryoScope, multi-focal plane images were taken every 15 min post-IVF through Day 7 of embryo culture. Early embryonic time points were observed and annotated in four replicates of 12 embryos; first cleavage (43/48 embryos, 30.1 ± 4.8 h average), second division (41/48 embryos, 40.0 ± 5.5 h average), third division (35/48 embryos, 50.5 ± 10.5 h average), compaction (34/48 embryos, 112.1 h ± 9.5 average), blastocoel cavity formation (30/48 embryos, 112.1 ± 10.9 h average), blastocyst formation (29/48 embryos, 153.9 ± 14.1 h average), expanded blastocyst (26/48 embryos, 165.9 ± 12.5 h average) and hatching blastocyst (17/48 embryos, 175.0 ± 9.1 h average). Embryos were graded based on morphology and blastocyst development based upon IETS Manual (grade 1: 31% (n = 15), grade 2: 19% (n = 9), grade 3: 4% (n = 2), grade 4: 2% (n = 1), degenerated: 44% (n = 21)). In this study we were able to confirm that bovine embryos could develop to a blastocyst stage in the EmbryoScope, with an overall embryo development rate of 54.2% (n = 26/48). Our overall conclusion is that the EmbryoScope can be a technology to monitor early embryonic developmental time points in bovine, and consequently could allow for the discovery of new embryo quality markers.