46 Use of time-lapse imaging technology to assess relationships of morphological and phototextural attributes of presumptive ovine zygotes and early embryos with their developmental competence in vitro

Abstract

The assessment of morphology and digital image opacity may provide valuable information on embryo viability because such traits are linked to embryonic gene expression, metabolism and ultrastructure. Time-lapse imaging has been used in research to monitor the dynamic nature of the developing pre-implantation embryo, which includes capturing alterations in various morphological parameters over time. The present study examined the effectiveness of time-lapse technology in assessing several morphometric and phototextural parameters for predicting the developmental potential of ovine embryos. The development of 37 long wool sheep embryos from IVF to the blastocyst stage was monitored and evaluated using Primo Vision time-lapse imaging technology. Image-Pro Plus software was then used to measure zona pellucida thickness, embryo diameter, cellular grey-scale pixel intensity and heterogeneity, and total area of the perivitelline space. A one-way analysis of variance (ANOVA) was done using SigmaPlot^® 11.0 for all attributes at various time points during embryo development [i.e. presumptive zygote stage, t(0); first cleavage, t(2) or t(3); second cleavage, t(4) or t(6); and third cleavage, t(7) or t(8)]. Our results indicate that most parameters analysed did not differ among embryos varying in their developmental fate, with the exception of the perivitelline space area, which was greater (P < 0.05) for non-dividing embryos than for future blastocysts at the presumptive zygote stage (4040 ± 4137 vs. 857 ± 642 µm², respectively; mean ± s.d.). Consequently, the measurement of perivitelline space at t(0) could be used to predict developmental potential of in vitro-produced ovine embryos, but further investigation is required.