Séralini’s rat-feeding trial (part 2)

Professor Gilles-Eric Séralini is a French scientist researching pesticides and GM (genetically modified, genetically engineered) crops. A research paper from his team was published in 2012, retracted (withdrawn) in 2013 and republished in 2014. Here it is.

This is the second in a series of blog posts in which I comment on Prof Séralini’s study.

The study was a feeding trial in which rats (Rattus norvegicus) ate a GM maize (corn, Zea mays) called NK603 from Monsanto and Monsanto’s weedkiller Roundup (active ingredient glyphosate) which NK603 had been engineered to resist.

Yesterday I said that NK603 was made using a gene gun to insert a bacterial gene. The gene gun’s relevant because for GM crops made that way, it’s relatively easy to get a license.

But licensing NK603 wasn’t completely easy for Monsanto. The United States’ Animal and Plant Health Inspection Service (APHIS), which regulates GM crops among other things, doesn’t mention NK603 on this list of GM plants which APHIS doesn’t regulate. It didn’t regulate those plants for the pseudoscientific reason that a plant pest (that is, Agrobacterium tumefaciens) wasn’t used to make them.

For NK603, Monsanto had to earn APHIS approval. Here’s Monsanto’s report of NK603 safety testing, published on Monsanto’s website in 2002. ‘NK603 and its progeny are no different from corn varieties developed through traditional breeding methods, except for the introduced trait [the glyphosate resistance]… These assessments were performed using the principles outlined by independent international scientific bodies such as the Organization for Economic Co-operation and Development (OECD), the United Nations World Health Organization (WHO) and the Food and Agriculture Organization (FAO)… and are consistent with country-specific regulations in the U.S., Canada, the EU and other countries.’

Monsanto’s experiments included gavage (force-feeding by stomach tube) to lab mice (Mus musculus). Those experiments showed that the protein which makes NK603 and other Roundup Ready crops tolerate glyphosate isn’t acutely (suddenly) toxic to mice.

Monsanto also told us, ‘Two key animal feeding studies have been completed using diets incorporating raw corn grain or ground grain containing corn event NK603. The animal feeding studies included a 42-day chicken [(Gallus gallus domesticus)] study and a 90-day rat study… Rats were fed one of the following diets for 13 weeks: diets containing… NK603 or [non-modified] corn grain; or [commercial] diets containing [non-modified, ground corn] grain… clinical parameters… and pathology findings in the animals fed diets of… NK603 compared favorably to [the other] rats… The results of this study confirm the comparability of corn event NK603 to the nonmodified control and the commercial grain diets…

‘The absence of biologically relevant differences in all growth, feed efficiency, histological and clinical parameters studied in either chickens or rats when compared to non-modified control and commercial corn grain confirms the compositional and nutritional equivalence of corn containing the event NK603, the absence of any significant pleiotropic [additional] or unintended effects and the absence of toxicity of the [Roundup Ready] proteins. Both the chicken and rat feeding studies confirm the conclusions of human and animal health safety of corn event NK603 and the nutritional equivalence of corn event NK603 to conventional corn varieties.’

On the strength of these safety tests, said Monsanto, ‘[Maize/corn] NK603 was commercialized in both the U.S. and Canada in 2001.’

Not good enough, said Prof Séralini. Here are his main critiques of Monsanto’s safety testing:
– it was short-term (only 13 weeks)
– it didn’t consider the adjuvants (extra ingredients) which are mixed with glyphosate to make Roundup.


About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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2 Responses to Séralini’s rat-feeding trial (part 2)

  1. Pingback: Séralini’s rat-feeding trial (part 3) | Science on the Land

  2. Pingback: Séralini’s rat-feeding trial (part 4) | Science on the Land

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