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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.



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.



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Comments on statistical methods for safety assessment published

March 6, 2018


In safety assessments a large number of non-target effects  has to be analysed statistically. A recent paper published in the Journal of Agricultural and Food Chemistry advocates an approach which leads to over-optimistic conclusions. In a recent Correspondence to this journal the concerns about the misapplication of methodology are explained. See: Safety Assessments and Multiplicity Adjustment: Comments on a Recent Paper, available on the Journal of Agricultural and Food Chemistry website at http://pubs.acs.org/doi/abs/10.1021/acs.jafc.7b03686.

Registration for Final Conference open

1 March, 2018


On April 16, 2018 G-TwYST organises a conference on general conclusions and recommendations from three scientific projects: G-TwYST, GRACE and GMO90+. Registration for this conference is compulsory and can be done by completing the registration form at the G-TwYST website. Registration is open until April 6, 2018.

More information, including a preliminary programme, is available on the G-TwYST Final Conference webpage.