Animals Raised on Genetically Engineered Feed Are Different

Even in the European Union where there is mandatory labeling of GM ingredients in food and feed, there is no mandatory labeling as yet of meat, dairy products or eggs from animals fed on GM feed (GM corn or soy, for example).

Even though such labeling is favored by consumers, and is justifiable purely in terms of transparency, the food industry has tried to make out that GM feed fed to animals makes no difference either to the animal or the final product. Research shows both claims are scientifically unsupported.

In this context, Prof Jack Heinemann has produced an exhaustive review of the literature. Item 1 is GM-Free Cymru’s excellent brief summary of his report, and also sets it in the context of a landmark ruling by the New Zealand (NZ) Commerce Commission. Item 2 draws on the report to give more detail.


In a landmark ruling, the NZ Commerce Commission has accepted evidence from Prof Jack Heinemann, from an exhaustive review of the literature and on the basis of his own extensive professional experience, that animals fed on GM components ARE different from those which are reared using non-GM feed. This is a direct challenge to EFSA and FSA, who have maintained consistently that there are no differences between GM- fed and non-GM-fed animals, and that there is therefore no need for labeling or segregation of feed supplies to meet consumer demand for GM-free products.

This issue came to a head because of complaints that NZ poultry producer Inghams claimed, in a high-pressure advertising campaign, that its chickens contained no GM ingredients, in spite of using up to 13% GM soy-based feed.

In one of its adverts, Inghams said: “Research confirms that animals that consume feed with a component of GM are no different compared to animals that have been fed a low GM or GM free diet.”

The Commission has now told Inghams that it was breaching the Fair Trading Act by making false or misleading claims. Inghams continued to argue on its website that the use of GM soy did not compromise an absolute GM-free status and animals that ate feed with a GM component were no different to animals that may have been fed a low GM or GM-free diet. This position was verified by numerous feeding studies, the website said. The company cited publications by a New Zealand Royal Commission, the Royal Society and the Federation of Animal Science Societies. However, those publications were at least 7 years old; and the company accepted the CC ruling and stopped the advertising as soon as Prof Heinemann’s investigation was commenced.

Prof Heinemann’s Report, entitled “Report on animals exposed to GM ingredients in animal feed” (July 2009), makes interesting reading. It surveys all of the published animal feeding studies which are cited by EFSA, FSA and other bodies, and subjects them to a careful analysis. He refuses to be drawn on human health and safety safety issues (since that was not his
brief) but concludes that there are many deficiencies in the studies which purport to show “no effects” from the consumption of GM animal feed.

Sometimes, in animal feeding experiments, GM components have been used in both the test group and the control group, which would have the effect of masking GM effects. Many animal feeding experiments are too short to reveal physiological changes. Other deficiencies are related to variability in the GM DNA of feed supplies, the sensitivity of the testing methods used, and the use of surrogate proteins rather than whole GM feed in the testing protocols.

Nonetheless, there are abundant studies (including some conducted under the auspices of the GM industry itself) that show statistically significant physiological changes in GM-fed animals, and that reveal the presence of “DNA and protein unique to GM plants within animals and animal products.”

Prof Heinemann also concludes: “There is compelling evidence that animals provided with feed containing GM ingredients can react in a way that is unique to an exposure to GM plants. This is revealed through metabolic, physiological or immunological responses in exposed animals.”

This is a very important study which should form the basis of a direct challenge to EFSA and FSA to change the wording on their websites and to abandon their fondly-held beliefs that GM components fed to farm animals do not enter the animal and animal product food chain.

2. Report on animals exposed to GM ingredients in animal feed
Prepared for the Commerce Commission of New Zealand
by Professor Jack A.Heinemann, PhD
24 July 2009
Summarized by GMWatch.

This report addresses the questions:

*could DNA from GM plants be transferred to the animal?
*could GM plants be incorporated into other products sold as chicken products, including bread or stuffing?
*could proteins from GM plants be transferred to the product or could the GM feed alter metabolites [any substance involved in metabolism, either as a product of metabolism or as necessary for metabolism] in the animal?
*could GM feed cause physiological or immunological responses in the animal?

Summary of conclusions

There is substantial literature that reports the detection of DNA and protein unique to GM plants within animals and animal products. Based on studies, it is not possible to conclude that animals and derived products are free of GM material when they have been exposed to GM plants through i) feeding, ii) proximity to other animals on GM feed, or iii) subsequent processing. The most consistent finding in the literature is that animals not exposed to GM feed were unlikely to be contaminated with GM material.

There is compelling evidence that animals provided with feed containing GM ingredients can react in a way that is unique to an exposure to GM plants.
This is revealed through metabolic, physiological or immunological responses in exposed animals. In the absence of appropriate testing, we can’t assume that raising an animal on GM feed will not affect the final product ­ even if there is no detectable residue from the GM material.

The cumulative strength of positive detections reviewed in studies leave no unreasonable uncertainty that GM plant material can transfer to animals exposed to GM feed in their diets or environment, and that there can be a residual difference in animals or animal products as a result of exposure to GM feed.

On current GM policy for retailers in Europe

Retailers are linking the use of GM feed with the GM status of their animal products. For the United Kingdom and Ireland:

“All of Marks & Spencer’s fresh meat and poultry, salmon, shell eggs and fresh milk comes from animals fed on a non-GM diet. The Kepak Group, which controls 60% of Irish beef exports, requires some farmers who produce meat for its flagship KK Club brand to exclude the use of GM animal feed,

“All Kepak’s chicken meat comes from birds reared on a vegetarian, non-GMO diet. The Silver Pall Dairy in Co Cork has signed multi-million euro foreign direct investment deals with Baskin Robbins (the world’s largest ice-cream retailer) and with Ben & Gerry’s, to produce GM-free ice cream (made from milk from cows fed a certified non-GM diet) for the European market.

“Tesco, Sainsburys, M&S and Budgen Stores all have quality labels for meat and dairy produce from livestock fed on certified GM-free animal feed. All of Marks & Spencer’s fresh meat and poultry, salmon, shell eggs and fresh milk comes from animals fed on non-GM diet. Moreover, standard poultry sold In most UK supermarkets now carries a label certifying GM-free feed”.

Similar practices are reported for Italy, France and Switzerland.
TraceConsult, which describes itself as a consultancy, reported on 20 July
2009 that the Swedish Dairy Association “were suddenly unable to continue their claim of supplying GMO-free milk” due to inadvertent distribution of GM feed to member farmers.

On whether consumers can avoid eating GM DNA in animal products

Would a consumer eating an animal raised on GM feed be able to avoid ingestion of DNA, protein or other substances unique to a GM plant, or able to avoid animal physiological or immunological responses to substances unique to GM plants? According to the evidence, no.

The research is clear on the following. If a consumer wanted to avoid eating GM DNA, then this consumer would have a high likelihood of success through purchasing meat products from animals raised on GM-free feed. For products that are breaded or stuffed, that consumer could probably avoid exposure to GM DNA if the ingredients in the breading and stuffing were certified organic or GM-free. If a consumer wanted to avoid eating proteins or metabolites unique to GM plants, then this consumer would have a high likelihood of success purchasing meat products from animals raised on GM-free feed. If a consumer wanted to avoid the ingestion of metabolites or proteins in animals that were only present, or present at different concentrations, when the animal was fed a GM plant, then this consumer would have a high likelihood of success through purchasing meat products from animals raised on GM-free feed.


On Inghams’ GM policy

Inghams is a major chicken and animal feed producer based in Australia.
Inghams states:

“Inghams is committed to sourcing non-GM ingredients for its poultry feeds and uses its best endeavours to source non-GM ingredients. Because these ingredients must meet specific quality standards and be available in quantities that are economically sustainable, Ingham chickens may sometimes consume poultry feed which could contain GM ingredients. This does not however compromise the absolute GM-free status of Ingham chicken products.”

“Research confirms that animals that consume feed with a component of GM are no different compared to animals that have been fed a low GM or GM free diet.”

“Inghams meets or exceeds all regulatory guidelines, script of practice and standards in New Zealand and Australia…As is the case with all Inghams products, our chickens contain no GM content and are not genetically modified.”

“The use of GM Soya in feed does not compromise the absolute GM-free status of the poultry products the company produces. Animals that eat feed with a component of GM Soya are no different to other animals that may have been fed a low GM or GM-free diet.”

However, all of the documents that Inghams uses as references for its position are at least seven years old, which is very old in such an active area of science and intense public interest. Importantly, one of the three references used, the UK Royal Society’s 2002 Update, does not address the issue of what constitutes “GM free”. It mentions a few older animal studies looking for detection of DNA in animals fed GM feed, and concludes that “DNA present in food can find its way into mammalian cells at some low frequency”.

The NZ Royal Commission reported … that they had heard from a variety of sources, including the predecessor of Food Standards Australia New Zealand and a submitter from Iowa State University that there were as of 2000-1 no detectable human health issues proven to be related to the use of GM plants as animal feed, and that under present labelling laws animals that consumed GM plants were not considered “genetically modified”. While the Royal Commission deliberated on the evidence of safety to humans, I could find no deliberation on the specific issue of whether chickens or other food animals fed GM plants would constitute the use of GM ingredients. … In sum, the references that Inghams Enterprises uses to support its claims are both out of date and of questionable support for its policy position.


*There is evidence of DNA unique to GM plants in animals given GM feed – but DNA is inconsistently detected:

Pigs were fed on controlled diets with some groups receiving 60% GM and some conventional maize. DNA unique to the transgene used in GM maize event Btl 1 was detected in pig stomachs, small intestine (duodenal, ileum), rectal and cecal contents but not in peripheral blood.


In a survey of milk products sold in stores in Italy, researchers found evidence of target DNA unique to GM plants in 38% of samples, including those labelled “organic”.


GM plant-specific target DNA was detected in the gastrointestinal (GI) tract of rainbow trout fed on a defatted GM soybean variety. The target DNA was detected for up to three days post transfer to a non-GM diet. This DNA was subsequently detected in leukocytes (white blood cells), head kidney and muscle. The target DNA was confirmed to be identical to the DNA in the GM soybeans.


A study on GM corn Bt176 fed to broiler chicken found that the DNA was not completely digested and could be detected for various lengths of time post-consumption in the crop, proventriculus (part of the stomach), gizzard, small intestine (duodenum, jejnum, ileum) and the caeca and rectum. The researchers reported evidence of plant-specific DNA in the blood, pectoral and thigh muscles, liver, spleen and kidney up to four hours after feeding, but did not detect the DNA unique to Bt176. No further detection was possible after 24 hours from feeding. This finding establishes that DNA can persist, circulate and transfer to deeper tissues although any particular fragment may fall below the detection limit.

In another study researchers found plant-specific DNA on chicken meat in supermarkets. While the target was not DNA unique to a GM plant, “it can be considered that an incomplete degradation of ingested DNA fragments may take place in the Gl tract of birds, enabling the detection of residual plant gene fragments. Due to a fast passage of feed through the GI tract of birds the appearance of DNA fragments might be more likely than for mammals”. DNA unique to a GM plant would be as likely to persist in animals fed GM-feed as any plant-specific DNA.

These researchers could not distinguish between several causes of DNA on the chickens, including residual undigested DNA from feed or contamination with feed dust which was not removed through the slaughter, preparation and packaging process. They confirmed that the DNA was from an external source and not because the chickens were genetically modified, because the target DNA was not detected in chicken embryos. For the purposes of this report, the cause is irrelevant because whether the GM-specific DNA is present as a partial digestion product on the meat or whether the meat is contaminated as a result of airborne material from GM-feed, it ultimately is on the chicken because of the use of GM feed.

Notable quotes from two studies:

1. “In summary, all results coincide with former propositions about a possible transfer of small DNA fragments from feed into distinct farm animals. First data are now available for pigs, and a recent report first observing foreign DNA within various chicken organs is supported” (p. 274 Klotz et al., 2002).

2. “Studies on DNA degradation in the GI tract suggest that foreign DNA ingested by animals is not completely degraded in their GI tracts” (p.
380-381 Chainark et al., 2008).


In rats fed on maize flour, a maize-specific single gene (as a surrogate for a GM-specific gene) was detected in the upper GI, from stomach to duodenum, and a gene maintained at multiple copies was detected throughout the GI down to the jejunum, ileum, caecum, colon and in the faeces.


A toxin gene unique to GM-maize was detected in rumen juice up to 5 hours after feeding. Targeting a smaller fragment to increase the efficiency of PCR allowed detection up to 24 hours after feeding.

Comment on EFSA report

A report from the European Food Safety Authority (EFSA) emphasised negative detections of DNA. A strength of their consideration of the issue of GM feed was to consider the entire supply chain including the effects of ensilaging and processing on the stability of DNA and proteins. They draw on a review by Flachowsky et al (2007). That review cites a 2003 abstract published in German describing the effects of processing on oilseed rape DNA. This abstract apparently reported a decline in the ability to amplify DNA specific to a variety of GM oilseed rape as it was toasted for longer times.

Nonetheless, plant-specific fragments of DNA were still detected after three toasting treatments. The most rigorous regime was a series of four toasting treatments from which a GM-specific DNA fragment could still be amplified.

Similarly, Flachowsky et al found that mechanical treatments had no effect on the stability of DNA from GM maize but ensiling (making silage out of the maize) did.

Nevertheless, a DNA fragment that was diagnostic of the GM plant was still amplified from ensiled maize after 200 days.

Flachowsky et al. proclaim in the abstract of their review that: “to date, no fragments of recombinant DNA have been found in any organ or tissue sample from animals fed” GM plants (p. 3 Flachowsky et al., 2007). This strong statement seems to have heavily influenced EFSA, but is perhaps misleading. As EFSA admit, the: “DNA introduced into crops through recombinant DNA technology is not different from other sources of DNA in the diet” (p. 2 EFSA, 2007) and this kind of DNA has unambiguously been found in organs and muscle. The proportion of DNA that is being targeted in studies is tiny compared to the total dietary DNA intake by the animal. Based on estimates of dietary DNA a cow might consume in a day (on feed with a 60% GM content), this target is only 0.000094% (or about one 1 millionth) of dietary DNA spread over the volume of the animal (Beever and Phipps, 2001).

Thus, any detection of a specific fragment of DNA, which is already at small concentrations in the animal, is actually dramatic evidence that DNA is not thoroughly degraded or digested. These positive detections serve to assure us that DNA survives degradation and digestion because single copy DNA markers can be recovered from animals.

Despite the strong statement in the abstract, the authors more cautiously conclude their review by saying: “However, in the case that plant DNA-fragments should be absorbed, it might be that transgenic DNA-fragments are also absorbed” (p. 27 Flachowsky et al., 2007).

In fact, Flachowsky et al. cite four studies in which a plant-specific DNA marker was found in animal muscle, organs, or tissues out of only seven total studies they cite for positive detections of plant-specific DNA in animals. Even in this far from exhaustive survey of the literature, more than 50% of the studies indicated that dietary DNA can pass beyond the GIT of animals and it is only a matter of chance whether the detected DNA is natural to the plant or is GM. Furthermore, unlike this report, their survey of the literature included papers published only up to 2005.

*There is there evidence of proteins unique to GM plants in animals fed GM plants, or metabolic differences in these animals – but not in every study.

This variability may be expected because of variations in exposure to GM material and accumulations of protein near the limit of detection.

Importantly, in the studies considered in this report that address this issue, control animals and diets were used. These control animals were fed non-GM equivalent material. In general, no GM-specific DNA or protein was detected from animals not fed material derived from GM plants.

*There is evidence of physiological or immunological responses specific to GM plants in animals fed GM plants:

Atlantic salmon fed on (MON810) GM maize-derived fish meal differed significantly in the activity of enzymes extracted from livers as compared to fish fed conventional maize meals.

Rats and mice

Rats fed GM rice producing the Ciyl Ab protein or PHA-E lectin were monitored for allergic responses. Some of the most significant changes were observed in rats on the GM diet for 90 days, where the PHA-E lectin caused a dose-dependent increase in IgA levels (indicating immune response), and the weight of lymph nodes were increased in these animals. Rats fed GM rice uniquely producing Cryl Ab had significantly higher white blood cell counts and male rats had reduced adrenals.

Most striking, this study found an antigen (i.e., Cry lAb or PHA-E)-specific immune response even in control animals (those not fed the GM rice). The authors said these results may be explained by inhalation of particles by the control group.

Thus, exposure to GM plant material could cause immunological changes in animals even if the material is kept out of their food but is used in animals contained within range of the feed dust.

In another study in which rats were fed meat using GM or non-GM soya, the rats has depleted precursors of a certain enzyme and disorganised pancreatic cells ­ changes that are often indicative of pancreatitis. The authors note:
“The results appear to indicate that rats fed on a GM diet suffered “a mild pancreatic injury with an adaptive response”.

In another study, mice fed GM soya diet to mice were compared to mice fed a non-GM control soya diet. Again, changes were observed in the pancreatic cells of GM fed mice. The authors interpreted these changes as an indication that in GM soya fed mice, the activity of the cell nucleolus is depressed and there could be more general effects on RNA processing, affecting the production of some enzymes in animals on GM feed.

Hepatocytes (liver cells) of mice were examined after they were maintained on a 14% GM or conventional soya diet. Hepatocytes are involved in numerous metabolic pathways: they metabolise and transform most of the products of digestion, and degrade and detoxify substances. Hepatocyte nuclei in the GM-fed mice had irregular shapes compared to controls.

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