Successful egg retrieval in white rhinos – another milestone for …

The procedure, first performed in northern white noses, took place at the Ol Pejeta Reserve in Kenya. Sheep are now artificially fertilized by the frozen sperm of a dead bull. The embryo produced in the lab would later be used by a surrogate mother, a cow with a white rhino of the South. The standing ovation is the result of the successful collaboration of the Leibniz Zoological and Animal Research Institute (Leibniz-IZW) with the Dvůr Králové Zoo, Avantea and Ol Pejet Conservation and the Kenyan Wildlife Service (KWS). The intervention was made possible by donations from the Federal Ministry of Education and Research (BMBF).

As the last remaining females of the northern white rhinoceros, Najin and Fatu, cannot withstand the pregnancy for physiological reasons, the hope for the salvation of these rhinos lies solely in the development of highly specialized assisted reproduction and artificial insemination techniques. Successfully searching for eggs is one of the many necessary steps – each one being a true pioneer – to save northern white rhinos from extinction. "The process is the result of years of research, development, adaptation and training. Both the method and the equipment needed had to be developed from scratch," explains Professor Thomas Hildebrandt (Leibniz-IZW) and Dr. Med. David Ndeereh (KWS), who led the proceedings. "We were able to collect a total of 10 eggs – five from Nain and five from Fatu, showing that both females are still capable of producing eggs and helping us to rescue these wonderful creatures."

The procedure was performed with a self-developed special medical device, with the help of which a team of ultrasound images guided the immature oocytes (oocytes) from the ovaries of the females. Animals were anesthetized during the procedure. "The anesthesia of the animals was uncomplicated, though both rhinos had not been immobilized for five years," say Frank Göritz (Leibniz-IZW) and Stephen Ngulu (Ol Pejeta).

"The fact that we managed to get 10 eggs is a great achievement and a testament to what we can achieve through the unique collaboration of scientists, zoo experts and animal rights activists in the area. There is hope for those animals that are in imminent danger of extinction," he adds Jan Stejskal of the Dvůr Králové Zoo Both animals were born at this Czech zoo.The collaboration between the Dvůr Králové Zoo, the Ol Pejet Conservation and KWS was made possible by December 2009 by Najin and Fatu – at that time accompanied by two already deceased men. – to come to Kenya She hoped to reproduce naturally near her natural habitat. Although reproductive tests were recorded, there was no pregnancy. "After a comprehensive health check in 2014, we came to the conclusion that both females could not give birth to offspring because of different health problems, "explains Dr. Robert Hermes, MD, of Leibniz-IZW. The two men – Suni and Sudan – died in 2014 and 2018. Samples of their sperm were stored in liquid nitrogen in the hope that assisted reproduction techniques could develop quickly enough to pass on their genes to the next generation.

"Yesterday's search for eggs allowed us to make the laboratory the reality of embryo production for the northern white rhino," says Cesare Galli of Avantee, an Italian laboratory for advanced animal biotechnology research and reproduction. Avantea will be planting oocytes with cryo-preserved sperm from Sunni and South.

"On the one hand, Ol Pejet's disdain for the fact that the number of northern white rhinos around the world has shrunk to just two individuals – a testament to the worrying way people treat their environment. On the other, we are very proud to be part of this groundbreaking work that represents the last glimmer of hope for northern white rhinos. We hope this will also help humanity understand that responsible environmental stewardship is not a luxury but a necessity, "says Richard Vigne, Ol Pejet's director.

"The decisions the world will make this week at the current CITES meeting in Geneva should be based on a concerted effort to save the last northern white rhinos. Current rescue efforts, using state-of-the-art reproduction techniques, should focus the world's attention on the suffering of all rhinos and make us avoid false decisions that disrupt law enforcement and increase demand for horns, ”says Hon. Najib Balala, Cabinet Minister for Wildlife and Tourism in Kenya.

"I am very pleased that this international collaboration will help us save the northern white rhino from extinction. Rescuing a rhino is very concerning to me, especially against the background that the last male Sudanese has died of old age," Brigadier (rtd) John Wawer, director, said Kenyan Wildlife Service.

The process is part of an international research project called "BioRescue", whose consortium includes Leibniz-IZW, Avantea and the Dvůr Králové Zoo. It is funded by the Federal Ministry of Education and Research (BMBF) and significantly further develops two approaches to species conservation. In addition to pioneering work in assisted reproduction and in vitro fertilization, the project team is also working on techniques and methods for producing artificial gametes (oocytes and sperm) from stem cells. Secured tissue samples from northern white rhinos are converted to pluripotent stem cells, which in turn can be further developed into primordial germs. They then mature to the oocyte or sperm – thus increasing both the number of gametes and the quality of in vitro fertilization. In addition, genetic diversity can be significantly increased. Access to stem cells is being advanced by partners at the Max Delbrück Center for Molecular Medicine (MDC) BioRescue Center, Kyushu University in Japan and Northwestern University in the US.

The entire egg retrieval process on August 22 was conducted in an ethical framework. This was done by animal ethicist Dr. Med. Barbara de Mori of the University of Padua collaborated with scientists and veterinarians of the consortium. "We have developed a dedicated ethical risk analysis that prepares the entire team for all possible scenarios of such an intervention and ensures that the animal welfare of the two individuals is greatly influenced by the design of the process," de Mori explains. Egg removal was carried out in accordance with Kenyan laws and international regulations.

Media Contacts:
Zoo and Wildlife Research Institute (Leibniz-IZW)
Steven Seet
Head of Media Relations and Scientific Communication

Dvůr Králové Zoo
Jan Stejskal
Director of Communications and International Projects
+420 608 009 072

Elodie Sampere
PR and communications
+254 / 727 341 612

Kenya Wildlife Service (KWS)
Paul Udoto
Head of Corporate Communications
+254 / 721 453 981

Scientific contact:
Zoo and Wildlife Research Institute (Leibniz-IZW)
Prof. Thomas Hildebrandt
BioRescue Project Manager and Head of Reproduction Management

Ol Pejeta Conservancy
Dr. Stephen Ngulu
Batch vet
+254 / 724 859 719

University of Padua
Department of Comparative Biomedical and Nutritional Sciences
Barbara de Mori
Director of the Ethical Laboratory for Veterinary Medicine, Animal Care and Welfare

Cesare Galli

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