White rhinos may be saved by test tube
IVF used for first time on rhinos as blueprint for fighting extinction of other endangered species
With only two female northern white rhinos alive, and no breeding partners left after the death of the last male, Sudan, at age 45, it looked like the end of the sub-species. But scientists have created a test-tube rhino embryo from the frozen sperm of a northern white male and a southern white female’s egg. They now plan to take eggs from the last two surviving northern whites and artificially inseminate them with the frozen sperm before implanting them into a southern white surrogate.
WHEN the last male northern white rhinoceros, 45-year-old Sudan, died in March, it looked as if the end of the sub-species was nigh.
With only two females alive, and no breeding partners left, the rhino was functionally extinct, and just a few years away from dying out entirely.
But in a world first, scientists have created a test-tube rhino embryo from the frozen sperm of a northern white male and the egg from a southern white female.
Because the procedure was successful, they now plan to take eggs from the last two surviving northern white females and artificially inseminate them with the frozen sperm before implanting them into southern white rhino females to act as a surrogate.
The team is confident that the northern white rhino calves will be born within the next three years, bringing the sub-species back from the brink of extinction.
“These are the first in vitro produced rhinoceros embryos ever,” said Prof Thomas Hildebrandt, head of the department of reproduction management at the Leibniz Institute for Zoo and Wildlife Research in Berlin. “They have a very high chance to establish a pregnancy once implanted into a surrogate mother. We will start with first implanting a hybrid embryo in the next few weeks and months to test the system. And after that, we will plant a white rhino into a surrogate mother. We hope within three years we will have the first northern white rhino calf born.”
Northern white rhinos are the most endangered mammal on Earth, and all conservation efforts to save them have been thwarted by poaching, civil war and habitat loss.
Since the Sixties, the population has fallen from 2,000 to just two remaining females today, mother and daughter Najin and Fatu, who are protected at Ol Pejeta Conservancy near Mount Kenya. The task of taking eggs from a rhino has never been attempted before, and scientists were forced to invent a special 6ft device to stimulate the female’s ovaries and collect the oocytes. The eggs were harvested from 20 southern white rhino females from zoos across Europe and then shipped to the Avantea medical laboratory in Italy for insemination with frozen sperm, which was collected from the last four northern white rhinos.
“In our lab we were able to develop procedures to mature the oocytes, fertilise them by intracytoplasmic sperm injection and culture them,” said Prof Cesare Galli of Avantea. “For the first time we had rhino blastocysts – an early stage of an embryo – developed in vitro, similarly to what we do routinely for cattle and horses.” The team is working on perfecting the embryo transfer and plans to implant the hybrid embryos into southern white rhinos this year. The first calves with northern white DNA could be born by 2020. The research was published in the journal Nature.