• Sudan, the world's last standing male, died on March 19, 2018, at the age of 45 years at Ol Pejeta Conservancy in Laikipia.
• The eggs were harvested August 22, 2019.
In a breakthrough, scientists have created two embryos of the almost extinct northern white rhino using IVF technology in a laboratory in Italy.
The milestone was announced yesterday by an international consortium of scientists and conservationists after the fertilisation in Avantea laboratory.
The embryos are now stored in liquid nitrogen to be transferred into a surrogate mother in the near future.
Sudan, the world's last standing male, died on March 19, 2018, aged 45 years at Ol Pejeta Conservancy in Nanyuk, Laikipia. His sperm had been extracted and frozen but not used in this case.
Eggs were harvested from a female.
In 2009, Sudan and another male named Suni — together with two females which were Sudan’s daughter Najin and granddaughter Fatu — were relocated to Kenya from the Czech Republic.
Scientists created the two embryos using eggs collected from Fatu, the youngest of the two northern white rhinos and frozen sperm from Suni. The eggs were matured and fertilised with sperm from males Suni and Saut. Suni died of natural causes in 2014.
Seven other white rhinos were moved from the Dvůr Králové Zoo in the Czech Republic in 2009, but they struggled to produce an offspring.
Although mating attempts were witnessed, there were no pregnancies.
The concerted efforts to save the species started after the deterioration of Sudan's health early last year.
“We brought 10 oocytes back from Kenya. After incubation, seven matured and were suitable for fertilisation including [four from Fatu and three from Najin] on August 22 this year," Prof Cesare Galli from Avantea said.
Avantea is an Italian lab of advanced technologies for biotechnology research and animal reproduction.
Before Sudan moved to the 700-acre enclosure at Ol Pejeta Conservancy, he spent many years in the Czech Republic. With climate conditions and natural vegetation closer to the northern white rhino’s native habitat, the semi-wild setting at the conservancy in Nanyuki was intended to improve chances of breeding.
It was hoped that breeding would be stimulated by the rhinos being closer to their natural environment.
Scientists concluded in 2014 that, owing to various health issues, neither Najin nor Fatu were able to carry a pregnancy.
Fatu’s eggs were injected with Suni’s sperm while Najin’s eggs were injected with Saut’s sperm using a procedure called Intra Cytoplasm Sperm Injection.
"Saut’s semen was of really poor quality and we had to thaw additional samples to find viable sperm for Intra Cytoplasm Sperm Injection," Prof Galli said.
Today we achieved an important milestone on a rocky road which allows us to plan the future steps in the rescue programme of the northern white rhino.Prof. Thomas Hildebrandt
After 10 days of incubation, two of Fatu’s eggs developed into viable embryos that were cryopreserved for future transfer. Najin’s eggs did not make it to a viable embryo despite the fact that one egg initiated segmentation.
The story of the northern white rhinoceros has for decades been a tale of decline.
The number of animals shrank to only two in 2018, rendering complete extinction as only a matter of time.
The milestone achieved in assisted reproduction may be a pivotal turning point in the future of the species.
The successful egg collection was a joint effort by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Avantea, Dvůr Králové Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service KWS.
Immediately after the collection of the eggs, they were air-lifted to the Avantea Lab.
“The entire team has been developing and planning these procedures for years," said Prof. Thomas Hildebrandt from Leibniz Institute for Zoo and Wildlife Research.
“Today we achieved an important milestone on a rocky road which allows us to plan the future steps in the rescue programme of the northern white rhino.”
Hildebrandt's Institute is an interdisciplinary research institute dedicated to developing the scientific basis for novel approaches to wildlife conservation.
(Edited by V. Graham)