Newly created embryo nourishes hope for the survival of the northern white rhino

Four months after the ground breaking first "ovum pickup" in August 2019, the team repeated the procedure with northern white rhinos Najin and Fatu on December 17, 2019, at Ol Pejeta Conservancy in Kenya. The animals were placed under general anaesthetic and nine immature egg cells (oocytes) -- three from Najin and six from Fatu -- were harvested from the animals' ovaries using a probe guided by ultrasound. The anaesthesia and the ovum pickup went smoothly and without any complications. The oocytes were transported immediately to the Avantea Laboratory in Italy. After incubating and maturing nine eggs, four from Fatu and one from Najin were fertilised with sperm using a procedure called ICSI (Intra Cytoplasm Sperm Injection). One out of five eggs from Fatu fertilized with semen from Suni developed into a viable embryo with the help of Geri, an innovative benchtop incubator with integrated continuous embryo monitoring capabilities designed to provide an individualized and undisturbed incubation environment, donated by Merck. The embryo is now stored in liquid nitrogen along with the two embryos from the first procedures.

Hon. Najib Balala, Cabinet Secretary for Kenya's Ministry of Tourism and Wildlife: "As a government, we are glad that the northern white rhino in-vitro fertilisation project by a consortium of scientists and conservationists from Kenya, Czech Republic, Germany and Italy collaborative partnership has been able to successfully produce three pure northern white rhino embryos ready for implantation into southern white rhino as surrogate mothers in coming months. This is a big win for Kenya and its partners, as the northern white rhinos are faced with the threat of imminent extinction, where only two of them, females Najin and Fatu, are left in the whole world and are currently hosted by Kenya. It's a delicate process, and for that, we thank the concerned parties, the Kenya Wildlife Service, Ol Pejeta Conservancy, Leibniz Institute for Zoo and Wildlife Research, Avantea Laboratory and Dvur Králové Zoo, for putting in all of their efforts in ensuring that the critically endangered species do not disappear from the planet under our watch. I urge the scientists to continue digging deeper into technology and innovations to ensure that not only this concerned species does not go extinct, but other species that are faced with similar threats. The fact that Kenya is at the centre of this scientific breakthrough also makes me very proud. It's amazing to see that we will be able to reverse the tragic loss of this subspecies through science."

Preparations for the next steps of the mission for saving the northern white rhino from extinction are underway simultaneously to the creation of embryos. The plan is to select a group of southern white rhinos at Ol Pejeta Conservancy from which a female could serve as surrogate mother for the northern white rhino embryo. To achieve the best possible results for work with pure northern white rhino embryos, the team relies on experience from similar embryo transfer procedures in southern white rhinos that have been performed in order to address reproduction challenges in European zoos. Despite the fact that more research is still needed, the team expects that a first attempt for this crucial, never before achieved step, may be undertaken in 2020.

In December 2019, the team also transported the semen of Sudan, the last northern white rhino male that died in March 2018, from Kenya to Germany. The aim is to use it in future for production of more embryos. However, as the semen was collected in 2014 when Sudan was already over 40 years old, it is necessary to test it first and then see whether it could be used for such purposes.

The egg collection, embryo creation and preparation for the embryo transfer is a joint effort by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Avantea, Dvur Králové Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service (KWS). The entire process is part of the "BioRescue" research. Its goal is to significantly advance assisted reproduction techniques (ART) and stem cell associated techniques (SCAT) complemented with a comprehensive ethical assessment carried out by the University of Padova for the benefit of the northern white rhinoceros. The consortium is partially funded by the German Federal Ministry of Education and Research (BMBF) and comprises   institutions from Germany, Italy, Czech Republic, Kenya, Japan and USA.