The study is the first on record to show that genetically modified goats' milk, which carries higher levels of the antimicrobial lysozyme, can help the recovery from diarrhoea caused by bacterial infection in the gastrointestinal tract.
The research in young pigs shows that milk from goats that are genetically modified to produce high levels of lysozyme may be effective in aiding recovery from diarrhoea.
Writing in PLoS One, the US-based research team said their hope is that such milk can eventually help prevent human diarrheal diseases that claim the lives of 1.8 million children around the world each year, and impair the physical and mental development of millions more.
"Many developing parts of the world rely on livestock as a main source of food," said Professor James Murray from the University of California - Davis, who led the research.
"These results provide just one example that, through genetic engineering, we can provide agriculturally relevant animals with novel traits targeted at solving some of the health-related problems facing these developing communities," said Murray.
The team also said their findings demonstrate the potential for food products from transgenic animals to one day also benefit human health.
Lysozyme is an antimicrobial protein that limits the growth of bacteria that are known cause intestinal infections and diarrhoea (like E. coli) and also encourages the growth of other beneficial intestinal bacteria.
The protein is considered to be one of the main components of human milk that contribute to the health and well-being of breast-fed infants.
Although lysozyme is produced at very high levels in human breast milk, and is also found in human saliva and tears, the milk that we drink from goats and cows contains very little lysozyme. This has prompted research efforts to boost lysozyme levels in the milk of such animals through genetic modification.
In the new study, Murray and colleagues fed young pig’s milk from goats that were genetically modified to produce higher levels of lysozyme - a protein that naturally occurs in the tears, saliva and milk of all mammals.
Pigs were chosen for this study as a research model because their gastrointestinal physiology is quite similar to humans, and because pigs already produce a moderate amount of lysozyme in their milk, the researchers said.
Half of the pigs were fed pasteurised milk that came from the transgenic goats and carried greater amounts of lysozyme — 68% of the level found in human breast milk. The other half of the pigs were fed pasteurized milk that came from non-transgenic goats and thus contained very little lysozyme.
The tem found that, although both groups of pigs recovered from the infection and resulting diarrhoea, those fed the lysozyme-rich milk recovered much more quickly than those receiving goats' milk without enhanced levels of lysozyme.
They also noted that the pigs fed the lysozyme milk were less dehydrated, had less intestinal inflammation, suffered less damage to the inner intestines and regained their energy more quickly than control group pigs.
No adverse effects were found to be associated with the lysozyme-rich milk, they said.
Source: PLoS One
Published online ahead ofprint, doi: 10.1371/journal.pone.0058409
“Consuming Transgenic Goats' Milk Containing the Antimicrobial Protein Lysozyme Helps Resolve Diarrhea in Young Pigs”
Authors: Caitlin A. Cooper, Lydia C. Garas Klobas, Elizabeth A. Maga, James D. Murray