Reporter 446, 7 February 2000
Animal feed prepared from genetically modified crops could be helping to produce antibiotic-resistant ‘superbugs’, according to new research in the biology department.
The researchers say such feedstuffs should be used with caution until more is known about possible consequences. Up to a third of the total US corn crop for 1999 was GM and silage made from GM crops is routinely fed to farm animals (though is not yet licensed in Europe).
The study found the grinding and milling processes used to prepare feeds leaves DNA intact in the animals’ stomach. DNA spliced into plants to give them immunity to pests could then be transferred to gut bacteria, making them resistant. The chances of this happening cannot be ruled out, the researchers say.
"If there is a significant risk of transmitting a transgene in the gut of farm animals it would seem sensible not to use GM crops as animal feed," said researcher Professor Michael Forbes. Scientists across the world are currently trying to establish just how big this risk of transmission really is.
The research found that many other ways of preparing animal feed did break up the DNA enough to render it ‘safe’. The extraction of vegetable oils from rapeseed and soyabean (the most common GM crops) totally degrades DNA and leaves no risk of subsequent transfer, Professor Forbes added.
The study also revealed that intact DNA in feedstuffs could only be completely fragmented by heating them to 95 degrees C for five minutes. "It would not be normal for many feed materials to be heated above 85 degrees," he said. "These findings will be of considerable importance to the feedstuff industry."
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