reply to post by Phage
Control group was 20, 10 females & 10 males .. there were 10 groups of 10 for each gender
Seralini based his study on the chronic toxicity part of OECD protocol no. 453. It states that for a carcinogenesis trial you need a minimum of 50
animals of each sex per test group but for a toxicity trial a minimum of 10 per sex suffices.
Seralini's team chose a chronic toxicity protocol to see if the signs of liver and kidney toxicity escalated into something serious, which they
clearly did, they did not set out to do a carcinogenicity study but a chronic toxicity study.
It is also worth remembering that Monsanto used 20 rats of each sex per group in its feeding trials but bizarrely, they only analysed 10, the same
number as Seralini. So Monsanto does not have a leg to stand on on this point! We wonder why Monsanto only analysed 10 rats out of 20. Were these
randomly chosen or were they selected because they were apparently healthy? Monsanto's data, like most such industry feeding trial data on GMOs, is
not published so we cannot check this.
Monsanto says that the increased mortality rates and tumour incidence "fall within historical norms for this strain of laboratory rats, which is known
for a high incidence of tumours".
By "historical norms" and "within this historical range", Monsanto means historical control data – data from various other studies that they find in
the scientific literature or elsewhere.
The only scientifically valid control for such experiments is the concurrent control, not historical control data. This is because scientific
experiments are designed to reduce variables to a minimum. The concurrent control group achieves this because it consists of animals treated
identically to the experimental group, except that they are not exposed to the substance under study. Thus, the only variable is exposure to the
substance(s) being tested – in the case of Seralini's experiments, NK603 maize and Roundup.
With this experimental design, any differences seen in the treated animals are very likely to be due to the substance being tested, rather than due to
irrelevant factors, as is the case with historical control data.
Even if we were to follow Monsanto's recommendation and use historical control data in evaluating Seralini's findings, the historical control data
cited by Monsanto is invalid because it relates to rats of a different origin (SD rats from Charles River Labs) than Seralini's rats (SD rats from
Harlan). Seralini took historical data on the Harlan SD rat fully into account in his study – and the results still show that the tumour increase
and other effects were statistically significant. The tumour incidence in the test groups in his study was overall around three times higher than the
normal rate observed in the Harlan SD rat strain he used, as reported in the literature.
Finally, the "tumour-prone rat" argument used by Monsanto and others to dismiss Seralini's findings of increased tumours is spurious. The key point
about Seralini's tumour findings was that the controls got some tumours, but the treated groups got significantly more tumours, and these appeared
sooner and were more aggressive than those of the control groups.
Given Seralini's results,it is now up to Monsanto to pay for a full carcinogenicity study on the NK603 maize, which, however, must be carried out by
independent scientists with no conflicts of interest.
As EFSA has repeatedly said, it is industry's responsibility to prove that its products are safe. Clearly it has not done that. So NK603 must be
withdrawn from the market until it has been proven safe.
edit on 27-9-2012 by AliceBlackman
because: forgot to add link