PHOTO: Stomach of a pig fed on non-genetically modified corn and soy. (Supplied)
AUDIO: GM safety concerns (ABC Rural)
MAP: Melbourne 3000
A joint Australian-US study has raised concerns about the safety of genetically modified crops fed to farm animals.
The study, conducted by researchers in South Australia and Iowa, showed pigs fed GM soy and corn crops had more stomach inflammation and heavier uteri than those fed non-GM feed.
"We found there was an increase in severe stomach inflammation in the GM-fed pigs - 2.6 times higher overall," said Lead researcher, Associate Professor Judy Carman,
Dr Carman says the study shows a clear need for further research into the health impacts of GM crops.
"The thing about pigs is that they have a digestive system that's very similar to humans," she said.
"Since we've got these major findings, some significant health related findings here in these pigs, I think it's important to consider that this might be happening in humans as well.
"We need to do further follow up studies to see if it is happening in people as well."
But the methodology and statistical significance of the study has been questioned.
Professor Rick Roush, from the University of Melbourne, says the fact that the study examined multiple variables without a specific hypothesis makes it open to 'procedure wise error'.
"If you test 20-30 things you'll expect to find at least one or maybe two that do appear to be unusual, but that doesn't make them statistically significant," he said.
A specific hypothesis isn't mentioned in the study and Dr Carman admits the researchers weren't expecting to find any difference in the weights of the uteri.
But she says there was an objective of studying inflammation in the pigs' stomach.
"We actually went there with a specific purpose in mind and we tested those," she said.
When you do that approach it doesn't really matter what other sort of things you might be measured on the side."
The research has been peer-reviewed and published in the Journal of Organic Systems. But Professor Roush says that doesn't guarantee its scientific credibility.
"If Dr Carman and her colleagues wanted to make a strong case about this, they would have managed to get this published in a journal that was actually focussed on toxicology," he said.
Dr Carmen insists the study is scientifically rigorous. But other scientists have also raised concerns about its methodology.
The study classified stomach inflammation into 'moderate' and 'severe'. While 31 per cent of the GM-fed pigs demonstrated severe inflammation (as opposed to 12 per cent of the non-GM fed pigs) only 25 per cent of the GM-fed pigs were classified as having 'moderate' inflammation, as opposed to 29 per cent of the non-GM fed pigs.
Professor Frank Dunshae from Melbourne University says when both moderate and severe inflammation are considered, the GM-fed pigs don't show a statistically significant incidence of inflammation.
"One could argue about what the significance is between moderate and severe," he said.
"It's all qualitative [in terms of] how you separate out mild, moderate and severe."
Professor Dunshae said the study is interesting and worth repeating. But he said the lack of difference in overall mortality and growth rates of the pigs means there is little cause for alarm from the findings.
"The fact that the animals grew at a similar rate indicates to me that the animals were of similar health in both groups," he said.
Dr Carman insists the findings are relevant and scientifically sound.
"There are a lot of ill people who walk around that are not dead," she said.
"These pigs were obviously not very well, but they weren't unwell enough to actually die from it.
"The GM fed pigs have actually moved from the moderate inflammation to the more severe category."
You can follow Flint Duxfield on twitter @Flintdux
Study questions feeding GM food to farm animals - ABC Rural - ABC News (Australian Broadcasting Corporation)
AUDIO: GM safety concerns (ABC Rural)
MAP: Melbourne 3000
A joint Australian-US study has raised concerns about the safety of genetically modified crops fed to farm animals.
The study, conducted by researchers in South Australia and Iowa, showed pigs fed GM soy and corn crops had more stomach inflammation and heavier uteri than those fed non-GM feed.
"We found there was an increase in severe stomach inflammation in the GM-fed pigs - 2.6 times higher overall," said Lead researcher, Associate Professor Judy Carman,
Dr Carman says the study shows a clear need for further research into the health impacts of GM crops.
"The thing about pigs is that they have a digestive system that's very similar to humans," she said.
"Since we've got these major findings, some significant health related findings here in these pigs, I think it's important to consider that this might be happening in humans as well.
"We need to do further follow up studies to see if it is happening in people as well."
But the methodology and statistical significance of the study has been questioned.
Professor Rick Roush, from the University of Melbourne, says the fact that the study examined multiple variables without a specific hypothesis makes it open to 'procedure wise error'.
"If you test 20-30 things you'll expect to find at least one or maybe two that do appear to be unusual, but that doesn't make them statistically significant," he said.
A specific hypothesis isn't mentioned in the study and Dr Carman admits the researchers weren't expecting to find any difference in the weights of the uteri.
But she says there was an objective of studying inflammation in the pigs' stomach.
"We actually went there with a specific purpose in mind and we tested those," she said.
When you do that approach it doesn't really matter what other sort of things you might be measured on the side."
The research has been peer-reviewed and published in the Journal of Organic Systems. But Professor Roush says that doesn't guarantee its scientific credibility.
"If Dr Carman and her colleagues wanted to make a strong case about this, they would have managed to get this published in a journal that was actually focussed on toxicology," he said.
Dr Carmen insists the study is scientifically rigorous. But other scientists have also raised concerns about its methodology.
The study classified stomach inflammation into 'moderate' and 'severe'. While 31 per cent of the GM-fed pigs demonstrated severe inflammation (as opposed to 12 per cent of the non-GM fed pigs) only 25 per cent of the GM-fed pigs were classified as having 'moderate' inflammation, as opposed to 29 per cent of the non-GM fed pigs.
Professor Frank Dunshae from Melbourne University says when both moderate and severe inflammation are considered, the GM-fed pigs don't show a statistically significant incidence of inflammation.
"One could argue about what the significance is between moderate and severe," he said.
"It's all qualitative [in terms of] how you separate out mild, moderate and severe."
Professor Dunshae said the study is interesting and worth repeating. But he said the lack of difference in overall mortality and growth rates of the pigs means there is little cause for alarm from the findings.
"The fact that the animals grew at a similar rate indicates to me that the animals were of similar health in both groups," he said.
Dr Carman insists the findings are relevant and scientifically sound.
"There are a lot of ill people who walk around that are not dead," she said.
"These pigs were obviously not very well, but they weren't unwell enough to actually die from it.
"The GM fed pigs have actually moved from the moderate inflammation to the more severe category."
You can follow Flint Duxfield on twitter @Flintdux
Study questions feeding GM food to farm animals - ABC Rural - ABC News (Australian Broadcasting Corporation)
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