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90-day feeding trial

G-TwYST is performing a 90-day feeding trial with GM maize NK603 according to the OECD Test Guideline 408 and the EFSA Guidance on conducting a 90-day oral toxicity study in rodents on whole food/feed. A 90-day feeding trial with GM maize MON810 has already been conducted in the GRACE project.

 

1 and 2 year feeding trials

A combined chronic toxicity (1 year) / carcinogenicity (2 year) study with GM maize NK603 is performed according to the OECD Test Guideline 453  and the scientific report of EFSA on the applicability of the OECD Test Guideline 453 to whole food/feed in a GLP-certified institution.

 

The near-isogenic counterpart of the GM maize is used for the formulation of the corresponding control diet.

 

Two dose levels

Two dose levels, a low and a high one, are tested. The low dose level (11% w/w) will be more than two times above the anticipated human intake (FAO Food Balance Sheets 2009) and the high dose (33% w/w) corresponds to the highest level of the whole feed that can be incorporated in the animal diets whilst avoiding nutritional imbalances. An additional high dose level of 50% is tested in the 90-day study.

 

Wistar Han Rcc rats

The studies are conducted with male and female Wistar Han Rcc rats. Two animals of the same sex are housed per cage. Body weight variation will not exceed 20% of the mean weight of all animals and each animal will be assigned a unique identification number.

 

Wistar Han Rcc rats have been selected because:

  1. they fulfil the general regulatory requirements for inclusion as part of toxicity evaluations;
  2. a vast amount of historical control data on this rat strain is available in the laboratory of SZU;
  3. this rat strain is presently being used in 90-day and the 12-month feeding trials with the GM maize MON810 by the GRACE project, so that this is the best choice when wanting to compare the study results obtained by the G-TwYST and GRACE consortia.

 

Analysis

The parameters for both the chronic toxicity phase and the carcinogenicity phase, including clinical observations, body weight, food/water consumption, haematology, clinical biochemistry and pathology, listed in the OECD Test Guideline 453 will be analysed. Animals will be sacrificed after 90 days, 12 months or 2 years, so that it will be possible to determine at which stage of the feeding trials histopathological alterations (including preneoplastic and neoplastic lesions) develop and whether earlier appearing lesions are indicative of the chronic lesions being observed after 2 years.

 

GLP-certified labs

The feeding trials will be carried out and analysed in GLP-certified labs at SZU and Roger Alison Ltd. The labs at SZU are GLP certified until the 15th of July 2018 (click here for the english and slovak version of the SZU certificate). Reporting on the periodic inspection of the  SZU facilities by the Slovak National Accreditation Service and two OECD delegates is also available here. Roger Alison is also GLP-certified until 2018.

 

 

Latest news

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1-year feeding study with MON810 on ARTE

In October 2016 ARTE broadcasted "OGM - Mensonges et vérités" (GMOs - Lies and truths) on French and German Television. In this 100 minutes long documentary Frédéric Castaignède sheds light on genetically modified crops, the impact on farmers, biodiversity and human health. We have selected and translated a fragment in which G-TwYST project leader Prof Pablo Steinberg presents the results of the 1-year feeding study with MON810 maize in the GRACE project.

 

The documentary provides a ‘snapshot’ of the GRACE final Conference which took place on November 9-10 2015 in Potsdam, Germany. We refer to videos on the GRACE Youtube channel  for a full account.

 

Paper published describing the statistical approach for equivalence testing in G-TwYST

An open access paper describing the statistical approach for equivalence testing in G-TwYST has now been published in Food and Chemical Toxicology. The method was tested on data from the GRACE project, as described in this paper. We will now progress by applying the method in the statistical analyses of the G-TwYST feeding trials, to be reported first in the statistical reports as project deliverables.

Highlights

  • An equivalence testing method is proposed to assess the safety of regulated products
  • We combine data from a current study with test and control, and historical studies with assumedly safe reference products
  • The method is illustrated with animal feeding studies using genetically modified and reference maize varieties
  • A high statistical power of the equivalence test is the basis for the equivalence criterion
  • Generalized fiducial inference is used to integrate uncertainties from the historical and the current data

 

van der Voet H, Goedhart PW, Schmidt K (2017). Equivalence testing using existing reference data:  an example with genetically modified and conventional crops in animal feeding studies. Food and Chemical Toxicology, 109: 472-485. https://doi.org/10.1016/j.fct.2017.09.044

G-TwYST Interim Report available

15 February 2017

 

The G-TwSYT team completed a publicly available Interim report with information about the progress that has been made in the first 1.5 years of the project. The report can be downloaded here.