Daily Double

Researchers in China have genetically engineered cows to produce human milk proteins, raising the prospect of one day breeding cattle that could replace the need for infant formula, PhysOrg reports. Humans have been drinking cows' milk for millennia, but it's still not easily digested and absorbed by human infants, making it an unsuitable nursing substitute. For mothers who can't breastfeed, infant formula is therefore the only option — but it can't fully meet an infant's nutritional needs either. Human milk contains a variety of distinctive proteins as well as human lysozome, which is key to fending off bacteria and boosting a baby's immune system.

To address this problem, Ning Li of the China Agricultural University and his colleagues introduced human lysozome and other human proteins into the embryos of Holstein cattle, which they then placed into surrogate cows. When these cows began lactating, their milk contained human lysozome and other human proteins, such as lactoferrin and lactalbumin, which also help fortify the body's immune system during development. The researchers then used a purification process to raise the fat content and milk solids, and to make the milk taste more like actual human breast milk. One day, they say, this genetically modified cow's milk could be available in grocery stores.

While that could be good news for infants who are spared baby formula, it has raised the hackles of those who distrust cloning and genetic modification, PhysOrg notes. (The researchers used cloning technology to insert the human proteins into the cows.) They worry about the potential risk of exposing sensitive infants to this genetically modified milk, as well as about the welfare of the cows themselves. In one of the study's experiments, for example, 10 of the 42 calves died shortly after birth and six others died within a few months.

Source: http://www.mnn.com/home-blog/green-news-roundup/blogs/daily-briefing-tues-108#milk