World first: successful embryo transplant paves way to save northern white rhino
The Pairi Daiza Foundation has been working for several years to save the northern white rhino, a subspecies of which only two remain in the world. The Foundation supports the BioRescue Project, a consortium of scientists trying to save the species using in vitro fertilisation techniques. Today, we are pleased to announce that the world's first gestation of a rhino after embryo transfer has been successful.
On 24 September 2023, Catherine Vancsok, Scientific Director of the Pairi Daiza Foundation, and Alicia Quiévy, Chief Veterinary Officer of Pairi Daiza, were in Kenya to lend their support to a crucial phase of research.
That day, scientists from BioRescue at the Ol Pejeta Conservancy (a nature reserve in Kenya) implanted two embryos in Curra, the southern white rhino chosen as a surrogate mother.
The eggs used to produce the embryos had been taken a few months earlier from Ellie, one of the southern white rhinos living at Pairi Daiza. Ellie's eggs were fertilised in vitro at Avantea laboratories in Cremona, Italy.
Thanks to the Pairi Daiza Foundation, scientists from the BioRescue Project have been collecting eggs from Pairi Daiza's southern white rhinos for several years. The aim is to be able to form an embryo from the southern white rhino and validate the protocol before testing it with the remaining genetic material from the northern white rhino.
A perfect transfer, achieved in difficult conditions
Two months after the transfer, Curra was unfortunately found dead in the nature reserve, she fell victim to a deadly bacterium from the same group that causes tetanus or botulism. It was the extremely heavy rain that caused the surrogate mother's enclosure to flood, releasing dormant spores of this bacterium of the genus Clostridium.
Curra's autopsy showed severe systemic poisoning, but also that she was expecting a 70-day-old male foetus 6.4 cm long.
In January 2024, DNA analysis of the foetus confirmed that the pregnancy was indeed the result of the embryo transplant carried out in September.
Thomas Hildebrandt, BioRescue project leader, Leibniz-IZW:
"The technique of embryo transplantation is well established for humans and domestic animals such as horses and cows. But for rhinos, it is completely unknown territory and everything, from the approach to the procedure protocols and the necessary equipment, had to be invented, developed, tested and proven in order to use it safely. Together with the team and many professional partners, I developed the devices to find and reach the location needed to insert the tiny embryo into a two-tonne animal. It took many years to get this done and we are happy to have proof today that the technique works perfectly. It is bitter that this step has been confirmed under such tragic circumstances, with the death of the Curra surrogate mother and her unborn calf, but I am sure that this validation of the protocol is a turning point for the survival of the northern white rhino and the health of Central Africa's ecosystems."
A northern white rhino baby in 2027?
The success of the embryo transfer means we can now safely move on to the next phase: the transfer of northern white rhino embryos. A dream that could become a reality in the next two to three years.
Since 2019, the BioRescue scientific conservation programme has produced and cryopreserved 29 northern white rhino embryos. These embryos are currently stored in liquid nitrogen at minus 196 degrees Celsius in Berlin, Germany, and Cremona, Italy, pending transfer to surrogate mothers of the Southern White Rhino.
Catherine Vancsok, scientific director of the Pairi Daiza Foundation, said:
"Helping the Northern White Rhino survive directly in Kenya shows the crucial role zoos play in species conservation. The Pairi Daiza Foundation runs a number of projects that bring together financial resources, human efforts and scientific research to help achieve conservation outcomes. The egg harvesting procedures of Ellie, the adult female southern white rhino residing at Pairi Daiza, were an essential step in the conservation chain. The BioRescue team, Pairi Daiza vets and park caretakers ensured that the welfare of the female southern white rhino was safeguarded at all times. Unfortunately, this on-the-spot setback is part of a long road ahead for all teams involved to achieve revolutionary conservation results. The Pairi Daiza Foundation relies on the power of human cooperation and the scientific process to get the northern white rhino back on its feet."
Johan Vreys