Vitrification of pig embryos for the worldwide dissemination of genetics using embryo technology

The VitriPig project started the 1st of April 2023. Last year we had several meetings with the Norwegian Food Safety authorities to get an Embryo Production and Collection Team approved in Norsvin so that we could start using the commercial non-surgical embryo transfer technique on farm. At the end of 2024 it was concluded that our own embryo laboratory was required to continue with research on embryo vitrification and transfer. The laboratory was then established and is in place since July 2024. In this laboratory, procedures for in vitro embryo production and vitrification of embryos are performed and optimized. Furthermore, in the spring of 2024 we successfully performed the first non-surgical embryo transfers in Norway with fresh embryos and 3 litters of piglets were born in June and August 2024. These are the first piglets born in Norway after non-surgical embryo transfer. Protocols and routines were established, and we continued with vitrification of embryos. Embryo transfer of vitrified embryos will start in the autumn of 2024 (Work Package 1). Since we now have our own laboratory in place, we will also start optimizing freezing and thawing protocols in collaboration with Wageningen University in the Netherlands (Work Package 2-3). The mathematical modelling of freezing and thawing curves started in 2023. We will study the effect of using different concentrations of cryoprotectants and exposure times during different the equilibration, freezing and thawing steps. We will also start investigating suitable in vitro embryo quality parameters that could be used in the different studies together with Inland Norway University of Applied Sciences in Hamar. (Work Package 3). In addition, in collaboration with NMBU/SEARCH in Sandnes we have been producing embryos from matured oocytes that were collected from live animals and we will start freezing those embryos to see if embryo quality and survival after freezing is better for in vivo matured oocytes (Work Package 3-5).

As an international pig breeding company, Norsvin is dependent on exporting genetics worldwide. Currently, this is mainly achieved with export of semen doses, but it slows down the customers’ progress by at least 50% compared to export of live animals. However, distribution of genetics through live animals has several challenges, so as a global breeding company we see distribution through embryos as the future solution. We will then obtain a faster increase in genetic gain, higher biosecurity and minimized risk of disease transmission, increased animal welfare and reduced carbon footprint, which all together positively impacts sustainable food production. However, implementation of embryo transfer in pig breeding is still a challenge, among other things due to the large number of embryos required for a successful embryo transfer and synchronization of the recipient sows. The ability to vitrify embryos will solve those challenges and will make it possible for us to distribute genetics through embryos. Therefore, the objective of this project is to establish and optimize pig embryo vitrification protocols that eventually can be used on farm. Within this project we will first gain knowledge about vitrification of embryos to obtain the first live born piglets after non-surgical transfer in Norway. Furthermore, we will optimize freezing and thawing curves by using mathematical modelling for achieving the highest possible embryo survival so that the protocols can be used on farm. In vitro embryo quality parameters will be assessed from the most optimal protocols, followed by an in vivo non-surgical embryo transfer study with vitrified embryos. If results are not promising, changes will be made again with the mathematical modelling. This project will provide us with new expertise, and it will contribute to the final implementation of embryo technology in pig breeding. This will greatly increase the competition advantages of Norsvin as a global pig breeding company.