In vitro embryo production in agricultural animals: morphokinetic profiling as a tool to investigate embryo viability

In response to a growing population and increasing demand for meat and dairy, the in vitro production (IVP) of embryos in agricultural animals is of vital importance to improving efficiency for breeding companies. IVP can accelerate genetic gain in breeding populations through reduced generational intervals, allow for the easier transport of female genetics through embryo transportation, and increase selection intensity. Similarly to human in vitro fertilization (IVF), agricultural IVP involves oocyte collection and maturation, fertilisation and incubation in the laboratory, and finally, the selection of the best quality embryos for transfer. This thesis aimed to improve techniques for embryo generation, selection and transportation for pig and cattle IVP.

For the first time at Canterbury Christ Church University (CCCU), a pig IVP system capable of supporting development to the blastocyst stage in semi-defined media was established. The novel use of the Geri® time-lapse system (TLS) for pig embryo culture showed that there are morphokinetic differences between pig embryos reaching the blastocyst stage and arresting embryos. The development of time-lapse technology (TLT) assessments to achieve automated embryo selection will no doubt be of vital importance to improving efficiency for the breeding industry to upscale IVP. Additionally, this work assessed methods for transporting IVP embryos, showing that cattle embryos can survive transit without temperature control, as well as demonstrating the novel use of the Gavi® automated vitrification device for cattle blastocysts, with acceptable post-thaw survival. It is also demonstrated how TLT could be used in research as a quality assessment tool, with both applications for the breeding industry and biomedical research. This work makes an important contribution to the field of agricultural IVP research by further establishing a role for TLT as a non-invasive assessment of embryo quality.