After successfully harvesting 10 eggs from the world's last two northern white rhinos, Najin and Fatu, on August 22nd in Kenya, the international consortium of scientists and conservationists announces that 7 out of the 10 eggs (4 from Fatu and 3 from Najin) were successfully matured and artificially inseminated. This was achieved through ICSI (Intra Cytoplasm Sperm Injection) with frozen sperm from two different northern white rhino bulls, Suni and Saut, on Sunday, August 25th. This is the next critical step in hopefully creating viable embryos that can be frozen and then later on transferred to southern white rhino surrogate mothers.
"We were surprised by the high rate of maturation achieved as we do not get such high rate (comparable to what we get with horse oocytes) with southern white rhino females in European zoos. The semen of Saut was very difficult to work with and to find three live sperms needed for the eggs of Najin we had to thaw two batches of semen. 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 cryopreserved for later transfer," said Cesare Galli of Avantea in Cremona (Italy) who led the fertilization procedure. The international research consortium to save the northern white rhino from extinction is led by Thomas Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research (IZW). Avantea is responsible for maturing the egg cells and creating viable embryos, further key project partners are Dvur Kralove Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service.
The results of possible embryo development are to be announced around September 10th. The research program (BioRescue) is funded by the German Federal Ministry of Education and Research (BMBF).