Scientists have created genetically modified cattle that produce "human" milk in a bid to make cows' milk more nutritious.
Published at 9:00PM BST 02 Apr 2011
The scientists have successfully introduced human genes into 300 dairy cows to produce milk with the same properties as human breast milk.
Human milk contains high quantities of key nutrients that can help to boost the immune system of babies and reduce the risk of infections.
The scientists behind the research believe milk from herds of genetically modified cows could provide an alternative to human breast milk and formula milk for babies, which is often criticised as being an inferior substitute.
They hope genetically modified dairy products from herds of similar cows could be sold in supermarkets. The research has the backing of a major biotechnology company.
The work is likely to inflame opposition to GM foods. Critics of the technology and animal welfare groups reacted angrily to the research, questioning the safety of milk from genetically modified animals and its effect on the cattle's health.
But Professor Ning Li, the scientist who led the research and director of the State Key Laboratories for AgroBiotechnology at the China Agricultural University insisted that the GM milk would be as safe to drink as milk from ordinary dairy cows.
He said: "The milk tastes stronger than normal milk.
“We aim to commercialize some research in this area in coming three years. For the “human-like milk”, 10 years or maybe more time will be required to finally pour this enhanced milk into the consumer’s cup.”
China is now leading the way in research on genetically modified food and the rules on the technology are more relaxed than those in place in Europe.
The researchers used cloning technology to introduce human genes into the DNA of Holstein dairy cows before the genetically modified embryos were implanted into surrogate cows.
Writing in the scientific peer-reviewed journal Public Library of Science One, the researchers said they were able to create cows that produced milk containing a human protein called lysozyme,
Lysozyme is an antimicrobial protein naturally found in large quantities in human breast milk. It helps to protect infants from bacterial infections during their early days of life.
They created cows that produce another protein from human milk called lactoferrin, which helps to boost the numbers of immune cells in babies. A third human milk protein called alpha-lactalbumin was also produced by the cows.
The scientists also revealed at an exhibition at the China Agricultural University that they have boosted milk fat content by around 20 per cent and have also changed the levels of milk solids, making it closer to the composition of human milk as well as having the same immune-boosting properties.
Professor Li and his colleagues, who have been working with the Beijing GenProtein Biotechnology Company, said their work has shown it was possible to "humanise" cows milk.
In all, the scientists said they have produced a herd of around 300 cows that are able to produce human-like milk.
The transgenic animals are physically identical to ordinary cows.
Writing in the journal, Professor Li said: "Our study describes transgenic cattle whose milk offers the similar nutritional benefits as human milk.
"The modified bovine milk is a possible substitute for human milk. It fulfilled the conception of humanising the bovine milk."
Speaking to The Sunday Telegraph, he added the “human-like milk” would provide “much higher nutritional content”. He said they had managed to produce three generations of GM cows but for commercial production there would need to be large numbers of cows produced.
He said: “Human milk contains the ‘just right’ proportions of protein, carbohydrates, fats,