In the past few years, somatic cell nuclear transfer and intracytoplasmic sperm injection (ICSI), laboratory strategies for creating a viable embryo from a body cell and an egg cell, have gained a lot of relevance, especially in horses. Few reports have been published exploring ovum pick up (OPU) and in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) in donkeys.
Still, some of the species and breeds of donkeys are considered endangered. According to scientists, such assisted-reproductive technologies could aid conserve these species.
In a new study, a research group from the University of Queensland has used a specialist IVF process known as intracytoplasmic sperm injection (ICSI) to create the world’s first successful donkey embryo. However, it is challenging to develop a viable donkey embryo, but scientists made it possible in collaboration with Argentinian and Spanish researchers.
This newly created donkey embryo is currently frozen in liquid nitrogen at a lab in Spain. Scientists are now searching for a suitable female for implantation. The embryo was created using donkey semen and an egg from different areas of the country. It is from an endangered European breed.
According to scientists, the study could save dozens of endangered donkey species. Plus, it could open up the possibility of helping donkeys – and other vulnerable species – by creating a ‘frozen zoo’ or genetic bank of embryos.
UQ’s Dr. Andres Gambini said, “With this new tool to produce embryos in the laboratory, we can help to repopulate a species if we need to.”
“There are many problems associated with inbreeding when trying to increase a species’ population, but this IVF technique means we can combine semen and eggs from donkeys with a different genetic background and create viable embryos.”
“Seven of the 28 European domestic breeds are in critical status, 20 are endangered, while wild donkey species are also in trouble. The reasons for this include theft, illegal slaughtering, decreasing grazing land, and people using them less.”
“Donkey embryos were much more difficult to work with, with a success rate of five to 10 percent, compared to horses which are about 30 percent. I wish I knew why donkey embryos were not produced easily!”
“We hope this research will lead to a more integrated donkey conservation program. We also hope to discover how to make IVF processes work for a wide range of endangered species.”
The project combined knowledge of semen preservation, embryo production, and egg collection from the National University of Río Cuarto, Buenos Aires’ National Council for Scientific and Technical Research, the University of Cordoba, the Autonomous University of Barcelona and UQ’s School of Agriculture and Food Sciences.
- Ana P. Flores Bragulat et al. Time-lapse imaging and developmental competence of donkey eggs after ICSI: Effect of preovulatory follicular fluid during oocyte in vitro maturation. Theriogenology. DOI: 10.1016/j.theriogenology.2022.10.030