A UC Davisresearchreported that pigs fed goat‘s milk modified with a human enzyme were better able to fend off E.coli bacteria than pigs fed unmodified goats‘ milk.
While theongoingresearch began in the 1990s, it has just been recently published in the May issue of Journal of Nutrition.
“The first goat was born in1999here on campus,” said James Murray,animal science professor who led the recent study with animal scientist Elizabeth Maga.
The researchers found that genetically-modified– or transgenic – goatsproducedmilk thatcontained high levels of an enzyme called lysozyme.
Lysozyme is a beneficial protein thatlimitsthegrowth of bacteriathat cause intestinal infections and diarrhea.Lysozymesare naturally produced in saliva,tears and milk of all mammals.
Thecontent of a lysozymenaturally produced in goats‘ milk,however,is only0.06percentofthat in human milk.In the study,transgenic goats were found to have produced milk with67percent as much lysozyme content as human milk.
Researchersthentested whether the milk from transgenic goatshelped pigs fend off bacteria in their intestines.
Two groups of young pigs were used in the experiment:One group was fed lysozyme-rich milk from transgenic goats and the other was fed milk fromregular goats.Half of the pigs were also given a dose oftheE.coli bacteria.
The results showed that pigs that were fed lysozyme-rich milkhad“significantly” lower levels of E.coli in their small intestines than did those who had milk from regular goats.
The researchers chose pigs for their study because pigs have digestive systems similar to humans.In a few years,Murray hopes to be able to apply his study to humans to test for improvements in gastrointestinal health.
“The ultimate goalisthat it will become useful for treatment for children in those parts of the world with high death rates caused by diarrhea,” Murray said.
Diarrhea leads to more than2million deaths in children under age5each year.More children die from diarrhea than from tuberculosis,AIDS and malaria combined,according to the World Health Organization.
About5million kids get diarrhea every year – 3millionsurvive,but a significant proportion get mental or physical retardation,or both,Murray said.Children in many areas of the world are unable toobtain lysozymes for various reasons such as a discontinuation of breast-milk production from their mothers.
“Our belief is that the goats that we’re producing will have a role in either preventing or treating childhood diarrhea,” he said.
The process to getting approved to test on humans,though,is a long and difficult one,Murray said.To do so,he must first be approved by the university’s review boardandthen by the Federal Drug Administration.
Another challenge posed toMurray is that of finding a company that would invest millions of dollars to the research,saidAlison L.Van Eenennaam,abiotechnologyextensionspecialist.
“I think that it’s got potential human health applications and animal health applications that are all positive,” she said. “The concern would be if it gets through the regulatory process because it’s so expensive.I think [lysozyme] is a protein that we follow everyday,so I don’t think there are any food health concerns associated with it.“
Murray believes that the chance of humans reacting to the lysozyme enzymeis slim,as it is present everyday in saliva.Goat milk does not seem to be much of a concernforhumans either.
“We drink goat milk all the time,” Murray said. “Goat milk is commonly consumed in many parts of the world and can bepurchased atSafeway!”
For those who areworried about the welfare of the goats and pigs used in the study,Murray said the animals are not harmed in any way.
“We found no adverse health consequences to the transgenic goats themselves or offspring that have been raised on the milk,” he said.
Murray will continue to work with the animals until he and other researchers find enough data and funding to move onto the next step.
Thecurrentstudy was funded by a grant from the UCD Academic Federation Committee on Research.
“We’re still working at the animal model level,” he said.“I hope that maybe in a year or two,we will have enough data from animal models to justify going toward humans.“
THUY TRAN can be reached at campus@californiaaggie.com.
