A historic step to save the northern white rhino was achieved yesterday when scientists announced that eggs from two surviving female rhinos had successfully been fertilised.
The Kenya Wildlife Service (KWS) said it is hoping that the resulting embryos will be brought back to Kenya to be implanted into southern white rhinos identified as surrogate mothers.
A consortium of scientists and conservationists from Kenya and their partners from around the world scored a first in wildlife conservation courtesy of technology that has been developed by an Italy laboratory.
The scientists announced that after successfully harvesting 10 eggs from the world’s last two northern white rhinos, Najin and Fatu, on August 22 in Kenya, seven out of the 10 eggs were successfully matured and artificially inseminated.
Ol Pejeta Conservancy Head of Conservation Samuel Mutisya said four eggs were from Fatu and three from Najin.
Sudan, the world’s last male northern white rhino, was euthanised in March last year at the age of 45 after suffering complications from an illness.
Najin was Sudan’s daughter while Fatu was the grand-daughter. Mutisya said Sudan had unsuccessfully tried to mate with females from a related sub-species of rhino found in southern Africa, while Suni, the second-to-last male died in 2014.
He said both Sudan and Suni were likely too old to be fertile by the time they were brought to Ol Pejeta from a zoo in the Czech Republic in 2009.
“This only left us with in-vitro fertilisation from preserved sperm as the last tool against extinction. Fertilising the eggs is a breakthrough for us and Kenya as a whole.”
Mutisya described the technology as a world-first and said it offered hope to other endangered wildlife species that could not reproduce through natural breeding.
“I thank the Government for supporting us through the Kenya Wildlife Services. Now we have the technology to save the white northern rhino and other species that face extinction.”
He said the gestation period of the northern white rhino is one-and-a-half years but given the technology used, which involves implantation of embryos into a surrogate mother, the world could hope to see a calf in three years.
Thomas Hildebrandt from the Leibniz-Institute for Zoo and Wildlife Research, who led the international research consortium to save the northern white rhino from extinction, said the feat was achieved through ICSI (intracytoplasmic sperm injection) with frozen sperm from two different northern white rhino bulls, Suni and Saut, on August 25.
“The result of the matured oocytes is a great success. It means that the collection technique and transportation, including a helicopter ride with KWS pilots, was ideal for the quality of the oocytes,” Prof Hildebrandt told The Standard.
He said his team hopes to achieve two embryos for each female, which would be better than the team’s expectations before start of the project.
“However, we believe that next time our recovery rate will be even higher so that the promise to have a live calf on the ground in three years’ time gets more realistic. The next oocyte collection is scheduled for December.”
Hildebrandt said this was the next critical step in hopefully creating viable embryos that can be frozen and later transferred to southern white rhino surrogate mothers.
“We were surprised by the high rate of maturation achieved as we do not get such high rates with southern white rhino females in European zoos,” he said.
Cesare Galli from Italy who led the fertilisation procedure said the semen of Saut was difficult to work with, and they had to thaw two batches of semen to find three live sperms for Najin’s eggs.
“Now the injected oocytes are incubated and we need to wait to see if any viable embryo develop to the stage where it can be cryo-preserved for later transfer,” said Cesare.
Cesare, who works for Avantea - a biotechnology research and animal reproduction laboratory - said they were proud to offer their unique know-how and expertise for a noble cause.
“After fertilisation, to become a viable embryo that can be implanted into the uterus takes about 10 days. With seven fertilised oocytes we expect - based on our previous experience with the southern white rhino - one or two embryos that will be cryo-preserved. But this is the first time that we have northern white rhino (NWR) eggs with NWR sperm, so we can only speculate for now,” Cesare said.
KWS Director General John Waweru said if the process succeeds, it will be a truly pioneering effort where a virtually extinct mammal with no living males has been brought back from the edge of extinction.
“We are crossing our fingers and hoping for the best.The resulting embryos will be brought back to Kenya and be transferred into identified southern white rhinos surrogate mothers. The resulting embryos will be shared between Kenya and the Czech Republic as per existing agreements,” Mr Waweru said.
He said Kenya was proud to be involved in saving the rhino species from extinction, adding that it was unfortunate to witness the near-disappearance of a species from the face of the earth.
“On behalf of the Kenyan government, I want to assure all project partners of our total support in subsequent parts of the project. We will facilitate acquisition of necessary permits, provide veterinary and other technical support as well as provide other resources that will be required to ensure the project’s success.”
Waweru thanked the National Environmental Management Authority, Kenya Veterinary Board and National Commision for Science, Technology and Innovation for their assistance in the project.
The results of possible embryo development will be announced around September 10.
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