WASHINGTON • The first litter of puppies conceived through in-vitro fertilisation (IVF) has been born, in a scientific breakthrough that could help in the fight against animal and human diseases, said researchers in the United States.
A female dog into which 19 embryos had been transferred gave birth in July to seven healthy puppies, according to the researchers from Cornell University and the Smithsonian Institution.
Two of the puppies are from a beagle mother and a cocker spaniel father, and the remaining five are from two beagle pairs, said Agence France-Presse.
The process of IVF, in which eggs are fertilised with sperm outside the body before the embryos are implanted into a female, has been in use since the 1970s to assist in human birth.
But scientists have long struggled to reproduce those results with dogs, in part because the canine reproductive cycle differs from that of other mammals, said Reuters.
"Since the mid-1970s, people have been trying to do this in a dog and have been unsuccessful," said Dr Alex Travis, associate professor of reproductive biology at the Baker Institute for Animal Health in Cornell University's College of Veterinary Medicine.
Female dogs ovulate only once or twice a year and their eggs tend to be less mature at that stage, according to the researchers.
The team faced several hurdles along the way, including in collecting mature eggs from the female oviduct - which is the canine equivalent of human fallopian tubes - simulating how the female tract prepares sperm for fertilisation in the laboratory, and freezing the embryos.
The researchers discovered that if they left the eggs inside the dog for an extra day, they could be fertilised successfully. They also found that adding magnesium to the cell culture properly prepared the sperm, reported The Telegraph.
The findings were published on Wednesday in the Public Library of Science One journal.
The scientists said they had built upon an earlier success. In 2012, Dr Travis' lab was able to produce Klondike, the first puppy to be born from a frozen embryo in the West.
The paper, whose co-author was Dr Jennifer Nagashima, a post-doctoral fellow at the Smithsonian Conservation Biology Institute, said the research could shed light on the genetic basis for numerous disorders that affect both dogs and humans.
Dogs share more than 350 similar heritable disorders and traits with humans, almost twice as many as any other species.
The research could also help eradicate heritable diseases in dogs. "With a combination of gene editing techniques and IVF, we can potentially prevent a genetic disease before it starts," said Dr Travis.
The technique has big ramifications for wildlife conservation. Scientists may be able to breed endangered species in captivity. For example, the African painted dog.
"We can freeze and bank sperm, and use it for artificial insemination. We can also freeze oocytes (egg cells), but in the absence of IVF, we couldn't use them," Dr Travis said. "Now we can use this technique to conserve the genetics of endangered species."
It was in 1978 that the first human "test tube" baby was born in Britain, the place where the technique was developed.