23 October 2000
Transgenic animal feed could affect dairy products
19 October 2000 (ENS)
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The genetically modified maize under scrutiny at a government public hearing in the UK has not been thoroughly tested and should not be sold commercially, according to two scientists called as expert witnesses, Wednesday. Called maize in much of the world, in North America the grain is known as corn.
Professor Bob Orskov, director of the International Feed Resource Unit in Aberdeen, Scotland, told the hearing he would not drink milk from cows fed the genetically modified (GM) fodder maize, known as Chardon LL.
The biotechnology company Aventis applied to the government to have Chardon LL included on the National Seed List, which would allow it to be grown and sold commercially as cattle feed.
Environmental group Friends of the Earth challenged the application, forcing a public hearing on the issue. Genetic modification involves altering an organism's genetic code or DNA in a way that does not occur naturally by mating or natural recombination. Selected individual genes can be transferred from one organism to another, sometimes between non-related species. Chardon LL, for instance, has been genetically engineered to be resistant to Aventis' own herbicide.
Genetic modification technology is routinely used in thousands of research laboratories worldwide and has resulted in many new products and processes such as industrial enzymes and medicines such as insulin and vaccines. But the use of genetic modification in agriculture and the food industry is currently the focus of intense public and political debate.
Proponents argue that GM technology could produce cheaper, more nutritious food that requires less weedkiller and pesticide. It could also grow food in colder or drier climates. Consumers, environmentalists and some scientists worry about risks to human health and the environment. They fear that GM crops could cause toxic or allergenic effects to humans. They are also concerned about large scale elimination of indigenous agricultural and natural species.
In the case of Chardon LL, Orskov is one such skeptic. He has been awarded the Order of the British Empire and is an expert on nutrition in the group of animals known as ruminants which includes cows. Orskov has published four books and is the author or co-author of more than 500 scientific publications.
"The scientific case put forward for this GM maize is not adequate," said Orskov, yesterday. "If the GM maize was approved for commercial growing in the UK then people would be justified in turning their back on consuming milk derived from it. As a scientist I wouldn't drink milk from cows fed GM maize with the present state of knowledge."
Orskov's criticism was shared by Dr. Vyvyan Howard, head of the Foetal and Infant Toxico-Pathology Group at the University of Liverpool. "My interpretation is that this GM maize has not been tested thoroughly," said Dr. Howard.
Howard and Orskov's main criticism of safety data presented by Aventis is that the firm has not tested Chardon LL on cattle, even though it is intended for their use. Instead, rats and chickens were fed a protein from oilseed rape - the same protein found in Chardon LL, according to Aventis.
Orskov was quick to point out that chickens and rats have one stomach, whereas ruminants such as cows have four. "The scientific case put forward for this GM maize is not adequate," said Orskov. "Chemical analyses of the kind reported cannot identity potential problems. We need to carry out proper, long term tests both on the effect of the maize silage for the microbes in the stomach of the ruminants which digest the feed and on the host animals. This has not been done."
Orskov warned Aventis and the government that the UK public could turn their backs on milk and switch to other foods. "This would have a disastrous effect on our dairy industry," he said. "Aventis needs to pay attention to this."
"If the GM maize was approved for commercial growing in the UK then people would be justified in turning their backs on consuming milk derived from it. And even if it could be scientifically proven to be harmless, there may still be a problem of consumer perception. The existing hurry seems to be supply pushed rather than demand led."
Howard dismissed claims by Aventis that some of the safety tests are not needed because the GM maize is not "materially different" from conventional varieties. After analyzing Aventis' safety data, Howard concluded that there were statistically significant differences in the composition of fat, protein and fibre between the GM maize silage and the non-GM counterparts. Statistically significant differences in fat and carbohydrate values of the GM and non-GM grain samples were also discovered.
"They [Aventis] have taken a protein from another plant and fed it to rats. I do not feel this can be used as a basis for making judgments about the safety of this GM maize with respect to cattle," said Howard. "What will happen if the maize is fed to cows as part of their diet? This is the question that needs to answered. The experiments carried out by Aventis are just a surrogate for well designed feeding trials, which would be both relevant and informative."
Food campaigner for Friends of the Earth Adrian Bebb said the public should be concerned about the scientists' criticisms. "Despite assurances from both government and industry, the reality is that the safety of these GM crops has not been properly tested," said Bebb. "If it wasn't so serious it would be laughable. It is clear that the government has not learnt anything from the BSE fiasco. Surely this GM maize cannot now be added to the national seed list and be sold to farmers."
Scientists believe that the UK's bovine spongiform encephalopathy (BSE) epidemic was caused by feeding cattle on meat and bone meal supplements that had inadvertently become contaminated with the disease agent. This occurred in the late 1970s and early 1980s, and established the infection in cattle. It was then magnified by the practice of feeding rendered material from slaughtered cattle back
to other cattle.
Otherwise known as Mad Cow disease, BSE is a progressive, fatal disease of the nervous system of cattle. When it occurs in humans it is known as Creutzfelt-Jakob disease. UK scientists suggest that a new form of Creutzfelt-Jakob disease may be caused by human exposure to BSE.
Concern over food contamination has been great enough to topple governments, as Belgium's governing coalition found to its cost in 1999. Contaminated animal feed was blamed for causing dangerously high levels of the cancer causing chemical dioxin in Belgian chicken, beef, pork, eggs, milk and by-products.
Worse, the Belgian government was said to have known about the contamination but withheld the information from the public and the European Union. In polls leading up to the June 1999 election, as many as one in every three Belgians said they planned to switch their voting intentions as a result of the food scandal.
[Entered October 20, 2000]