Northern White Rhinos are impressively bouncing back from the brink of extinction thanks to the dedicated efforts of scientist and conservationists.
In March and April 2021, an international group of scientists and conservationists working to save the northern white rhino from extinction by innovative assisted reproduction technology created four more northern white rhino embryos.
This is the most active set of procedures that the team of Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Safari Park Dvr Králové, Kenya Wildlife Service, Ol Pejeta Conservancy, and Avantea has ever performed, ranging from oocyte selection in Kenya to in vitro fertilization and cryopreservation in Italy.
Furthermore, the team announced the successful sterilisation of the southern white rhino bull Owuan in December 2020.
The bull will now be introduced to the female Ol Pejeta southern white rhinos, who have been established as possible surrogate mothers for prospective northern white rhino offspring.
Najin And Fatu
The only two northern white rhinos in the world are females Najin and Fatu at Ol Pejeta Conservancy in Kenya.
Since 2019, an international team of scientists and conservationists led by Leibniz-IZW has been collecting immature egg cells (oocytes) from the two females and artificially inseminating them with frozen sperm from deceased males in order to generate viable northern white rhino embryos.
The embryos will be transferred to southern white rhino surrogate mothers in the near future to produce northern white rhino offspring.
After placing Fatu under general anaesthesia, 19 oocytes were extracted from her ovaries using a probe powered by ultrasound on March 28th, 2021.
Fatu, Najin’s daughter and Sudan’s granddaughter, is the younger of the two northern white rhinos.
Both the anaesthesia and the ovum collection procedures went off without a hitch.
After incubation and maturation at Avantea’s laboratory in Italy, 14 of the egg cells were fertilized with thawed sperm from deceased northern white rhino bull Suni using an intra-cytoplasmic sperm injection technique (ICSI).
Four fertilised oocytes developed into viable embryos that are now stored in liquid nitrogen along with the five embryos already created in previous procedures.
There are now a total of nine embryos, all derived from oocytes collected from Fatu.
Embryo development was achieved with the help of Geri®, an innovative benchtop incubator with integrated continuous embryo monitoring capabilities designed to provide an individualised and undisturbed incubation environment, and donated by Merck.
During the most recent procedure, Najin, who is now 31 years old, was put under light sedation whilst standing and examined via ultrasound.
After the results of the ultrasound, the team decided not to attempt the procedure as she had not appeared to have developed enough promising oocytes.
The consortium will soon thoroughly discuss if and how to continue the oocyte collections with Najin, as ethical risk assessments are a pivotal part of the programme.
Another very important step in the success of the BioRescue programme was the selection and sterilisation of the southern white rhino bull Owuan in December 2020.
The animal was sterilised by the BioRescue team with a minimally invasive non-surgical procedure using state-of-the-art equipment.
The sterilisation went smoothly and without any complications. In March 2021, the BioRescue team confirmed via electroejaculation that the sterilisation was indeed successful.
Owuan has recovered well from the examinations and is up to his future role: as a sterilised bull, he will reliably indicate through his behaviour the reproductive cycle of potential surrogate mothers without any risk of impregnating them.
This information is a crucial prerequisite for transferring the embryos to surrogate mothers at the correct timing of their reproductive cycle.
Under the guidance of Kenya Wildlife Service, the team carefully planned the location of selected southern white rhino females for Owuan’s company and his introduction to them will take place in the coming weeks.
Bright Future For The Northern White Rhino
The BioRescue research programme, significantly funded by the German Federal Ministry of Education and Research (BMBF) and additional donors such as foundation Nadace ČEZ, the philanthropist Dr Richard McLellan and Merck EMD foundation, will continue with its ambitious plan to create more embryos from oocytes collected from the northern white rhino females in a three to four-month cycle as long as the COVID-19 pandemic allows for the team to travel to Kenya.
With the sterilisation confirmed and relocation of surrogates planned, the next milestone of the programme is getting within reach.