Cloned Cows' Milk Could Someday Replace Baby Formula

By Theodora Filis

Babies could someday drink human-like milk derived from herds of genetically modified dairy cows, which scientists say could supplement breast milk and replace baby formula.

Research, published in PLoS One, claims to be the first study to result in the production of a herd of cloned transgenic cattle expressing recombinant human lysozyme (rHLZ) in their milk.

Lysozyme, a bactericidal protein that protects human infants from microbial infections, and is found in only trace amounts in cow milk. The researchers said that the new transgenic milk may allow for the transfer of the nutritional aspects of human lysozyme in human milk to bovine milk.

“Our study not only describes transgenic cattle whose milk offers similar nutritional benefits as human milk but also reports techniques that could be further refined for production of active human lysozyme on a large scale,” said the authors, led by Professor Ning Li, the China Agricultural University, China.

Writing in the journal Public Library of Science One, Prof Li’s team said they used cloning technology to introduce human genes into the DNA of Holstein dairy cows. One variety of GM cows produced milk containing lysozyme – an antimicrobial protein found in breast milk that protects babies from infection. They also created cows that produced human lactoferrin, a protein that boosts the immune system.

A third human milk protein called alpha-lactalbumin was also expressed in the milk. Prof Li claims his team has boosted the milk’s fat content by a fifth and changed the levels of solids to make it close to the composition of human milk.

But campaigners said the creation of GM cattle was bad for animal welfare. In two experiments by the Chinese in which 42 GM calves were born, just 26 survived. Ten died soon after birth and six died within six months.

However, Professor Ning Li, insists GM milk would be as safe to drink as milk from ordinary dairy cows.

"The milk tastes stronger than normal milk. We aim to commercialize some research in this area in the 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.” said Ning Li

The move was condemned by campaigners who question its safety. Human milk differs from cows’ milk in several important ways. It contains high quantities of nutrients beneficial to a baby’s growth and immune system. Cows’ milk is much harder for a baby to digest, has less fat and fewer carbohydrates, and contains no antibodies that protect against disease.

Patti Rundall, of Baby Milk Action, said: “We need to have rules in place to safeguard human health. There could be incredible risks with these products that we don’t know about. Cows’ milk is never going to be like breast milk. It’s never going to be a living product like breast milk. Breast milk is species-specific – there is no element of risk.”

Prof Keith Campbell, a biologist at Nottingham University and a member of the team that cloned Dolly the sheep in 1996, said GM animals were not a threat to health unless scientists deliberately gave them a gene that made their milk toxic.

The modified milk could help boost sales of dairy products in Asia, where more than nine in ten people are lactose intolerant and cannot consume cows’ milk without suffering stomach upsets and cramps.

China’s rules on GM food are more relaxed than those in Europe. GM milk would not be allowed on sale in the UK unless it was approved by the European Union and passed stringent safety tests.