New! Sign up for our free email newsletter.
Science News
from research organizations

Five new embryos created after 10th oocyte collection in northern white rhinoceroses

Date:
September 9, 2022
Source:
Leibniz Institute for Zoo and Wildlife Research (IZW)
Summary:
Three years after starting its ambitious program to save the northern white rhino from extinction through advanced assisted reproduction technologies, the BioRescue consortium draws a positive interim conclusion: Following the 10th event of harvesting immature egg cells (oocytes) in the northern white rhino female Fatu, the international team produced five additional embryos -- bringing the total to 22 sired by two bulls. This nourishes the hope to eventually succeed in producing new offspring and give a keystone grazer of Central Africa a new future.
Share:
FULL STORY

Three years after starting its ambitious programme to save the northern white rhino from extinction through advanced assisted reproduction technologies, the BioRescue consortium draws a positive interim conclusion: Following the 10th event of harvesting immature egg cells (oocytes) in the northern white rhino female Fatu, the international team produced 5 additional embryos -- bringing the total to 22 sired by two bulls. This nourishes the hope to eventually succeed in producing new offspring and give a keystone grazer of Central Africa a new future. At the same time, the consortium places the highest value on respecting the life and welfare of the individual animals involved. Regular veterinary and ethical assessments of oocyte collection procedures show that Fatu handles the procedures well and shows no signs of detrimental health effects. BioRescue is supported by the German Federal Ministry of Education and Research (BMBF).

The 10th oocyte collection in northern white rhinos (NWR) was performed by a team of scientists and conservationists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Ol Pejeta Conservancy, Safari Park Dvůr Králové, Kenya Wildlife Service (KWS) & Wildlife Research and Training Institute (WRTI) on July 28, 2022, at Ol Pejeta Conservancy in Kenya. The BioRescue team was able to collect 23 oocytes from Fatu, the younger of the two remaining NWR females. Oocyte collections from Najin, Fatu's mother, were ceased in 2021 following an in-depth ethical risk assessment. The oocytes were immediately air-lifted to the Avantea laboratory in Cremona, Italy. Following maturation, 7 of the oocytes were fertilized using cryopreserved, thawed semen from the deceased NWR male Angalifu. Eventually, 5 embryos of Fatu were successfully produced and cryopreserved in liquid nitrogen.

This collection followed on from the 9th oocyte collection held at the same location and by the same team on April 24th. Out of 16 collected oocytes, 3 embryos were produced in the Avantea laboratory, again using the semen of Angalifu. Successful results of both procedures raised the total number of NWR embryos produced to 22 -- all of them from female Fatu, with half of them sired by the deceased male Suni who was born in Safari Park Dvůr Králové, Czech Republic, and the other half sired by Angalifu who lived in San Diego Zoo Safari Park, USA.

Once the protocol to transfer the embryos to surrogate southern white rhino (SWR) female recipients is optimized, the embryos will be the foundation of a new NWR population, eventually destined to step back into their ecological role as keystone grazers in Central Africa.

To set up suitable conditions for a successful embryo transfer, the team has been carefully following the interactions of the sterilized SWR bull Owuan, who serves as the oestrus detector, with the possible surrogate females that share an enclosure with him. Once the conditions allow it, the BioRescue team will attempt to conduct an embryo transfer -- first with SWR embryos to demonstrate that the whole procedure works properly before the team uses the extremely valuable NWR embryos. The team is currently considering whether adding more SWR females to the program might increase the chance of achieving the first successful embryo transfer.

Thomas Hildebrandt, BioRescue project leader and head of Department of Reproduction Management at Leibniz-IZW: "In 2019, one day before our worldwide first oocyte collection in NWR I said -- tomorrow we will change the world. Today I can say, we did: The 5 new NWR embryos created in one set of procedures are a new record in our mission to save the NWR from the brink of extinction. In total, we managed to produce and cryopreserve 22 pure NWR embryos from 158 oocytes collected during 10 collections: 148 from Fatu and 10 from Nájin. Our next aim is to successfully produce viable offspring by inventing and using new scientific embryo transfer methods and techniques. The ground breaking scientific work we are establishing here will lay the groundwork for future conservation rescue initiatives."


Story Source:

Materials provided by Leibniz Institute for Zoo and Wildlife Research (IZW). Note: Content may be edited for style and length.


Cite This Page:

Leibniz Institute for Zoo and Wildlife Research (IZW). "Five new embryos created after 10th oocyte collection in northern white rhinoceroses." ScienceDaily. ScienceDaily, 9 September 2022. <www.sciencedaily.com/releases/2022/09/220909162834.htm>.
Leibniz Institute for Zoo and Wildlife Research (IZW). (2022, September 9). Five new embryos created after 10th oocyte collection in northern white rhinoceroses. ScienceDaily. Retrieved March 28, 2024 from www.sciencedaily.com/releases/2022/09/220909162834.htm
Leibniz Institute for Zoo and Wildlife Research (IZW). "Five new embryos created after 10th oocyte collection in northern white rhinoceroses." ScienceDaily. www.sciencedaily.com/releases/2022/09/220909162834.htm (accessed March 28, 2024).

Explore More

from ScienceDaily

RELATED STORIES