Wild pigs and deer do not spread GM corn via feces or accumulate transgenic residues in meat

Oct 26, 2009

Deer stew, roast of wild boar, venison ragout - come fall, all varieties of game are in season for gourmets. However, ever since the worldwide surge in genetically modified corn, critical consumers' appetites have abated somewhat. After all, it was not clear precisely how wild animals digest transgenic corn and whether or not residues actually accumulate in meat, for example. Molecular biologists from the Technische Universitaet Muenchen (TUM) have shown that there is no need for concern - also with regard to the inadvertent dispersal of genetically modified corn via wild animal feces.

Only a few weeks ago we could still observe them: whole families of wild boar rummaging in the corn fields in early fall, feasting on corncobs. Corn - or maize, as it's known to scientists - is a high-energy delicacy for local game, which is why it is used specifically for winter feeding and to divert animals from farmers' fields. Today, with GM (genetically modified) maize acreage increasing worldwide, biologists are discussing a highly controversial question: What happens when a wild boar takes a snack in a transgenic maize field or when deer feed on imported GM maize in winter? Molecular biologists at the TUM can now provide answers to these questions.

With funding from the German Federal Agency for Nature Conservation, a research team from the TU München examined in detail how fallow deer (dama dama) and wild boars (sus scrofa) metabolize GM maize and whether they inadvertently disperse germinable transgenic seeds in the landscape via their feces. To find answers to these questions, the scientists working for Prof. Heinrich H.D. Meyer from the Chair of Physiology selectively fed fallow deer living in outdoor enclosures and wild boars kept in pens genetically modified corn chaff and grain corn for several weeks in a row. The respective control groups were fed conventional maize over the same time period. All the while the scientists collected samples of feces from every group to be analyzed for germinability at a later point in time.

After completing the experiment, the TUM physiologists took a number of samples from all of the wild animals: from the digestive tract, all internal organs, blood, muscles and other kinds of tissue. They then applied immunological techniques and polymerase chain reaction to look for transgenic components. They found them only in the digestive tract of GM-fed wild boars: Here they found evidence for small fragments of the gene that had been introduced into the GM maize. However, outside of the gastrointestinal tract the scientists found no trace whatsoever, neither in the tissue of wild boars nor in that of the fallow deer. Hence, there is no need to worry when enjoying a game dish: "The meat of the animals we examined was entirely free of transgenic components," said Prof. Meyer.

Organic farmers and environmentalists are much more concerned about the uncontrolled spread of GM maize via wild animal feces. Yet here, too, Prof. Meyer can ease everyone's worries. His team examined the collected samples of feces for intact maize corns capable of germination. A truly insignificant number makes it through the gastrointestinal passage at all: For wild boars a mere 0.015% of the conventional and 0.009% of the transgenic maize kernels were excreted intact. Only one single maize plantlet could then be grown under standard laboratory conditions, and one further seedling showed abnormal growth. The fallow deer were even tougher on the maize: Not a single intact and thus germinable maize corn could be found in their feces.

However, the digestion process is not as effective for all seeds and all animal species, as the scientists were also able to show. They had additionally fed all examined animal groups with conventional rape. They found not a single intact rape seed in the wild boar feces - but in those of the fallow deer there were plenty, and 13.6% of those were capable of germination. "This shows that such studies need to be conducted separately for all genetically modified plants," Prof. Meyer concluded.

More information:

• Wiedemann, S.; Lutz, B.; Albrecht, C.; Kuehn, R.; Killermann, B.; Einspanier, R.; Meyer, H.H.D.: Fate of genetically modified maize and conventional rapeseed, and endozoochory in (Sus scrofa). Mammalian Biology 74 (2009) 191-197. DOI:10.1016/j.mambio.2008.07.002

• Guertler, P.; Lutz, B.; Kuehn, R.; Meyer, H.H.D.; Einspanier, R.; Killermann, B.; Albrecht, C.: Fate of recombinant DNA and Cry1Ab protein after ingestion and dispersal of genetically modified maize in comparison to rapeseed by falDOI 10.1007/s10344-007-0104-4n Journal of Wildlife Research 54 (2008) 36-43. DOI 10.1007/s10344-007-0104-4

Source: Technische Universitaet Muenchen

Explore further: Ideology prevents wheat growers from converting to more profitable methods, new study shows

add to favorites email to friend print save as pdf

Related Stories

GMO maize strain safe: EU food agency

Jun 30, 2009

A genetically modified strain of maize, banned in some EU countries, poses no risk to health or the environment, the European Food Safety Authority declared Tuesday.

GM crop creates a 'superweed'

Jul 25, 2005

Cross-fertilization between genetically modified crops and wild plants -- believed nearly impossible -- has reportedly occurred in Britain.

An impossible coexistence: Transgenic and organic agriculture

Jun 30, 2008

The study was carried out by researcher Rosa Binimelis of the UAB Institute of Environmental Science and Technology. Binimelis is working on the European project ALARM (Assessing Large Scale Risks for Biodiversity with Tested ...

Recommended for you

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.