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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.

 

 

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G-TwYST Conclusions & Recommendations

29 April 2018

 

At a Conference held in Bratislava, Slovakia, on 16 April 2018, G-TwYST presented draft conclusions and recommendations regarding guidance on the design, conduct, interpretation, and analysis of animal feeding studies and their value for GMO risk assessment. A final version of G-TwYST Conclusions and Recommendations can be downloaded here.

Final programme 28/29 March available

18 March 2018

The final programma for the G-TwYST stakeholder consultation workshop on March 28 and 29 in Antwerp is available now and can be downloaded here.

 

This workshop, which is open for interested stakeholders, will focus on the draft results of a 90-day feeding study with 50% inclusion rate of GM maize NK603, as well as a combined chronic toxicity and carcinogenicity feeding study and the overall draft conclusions. Also included in the scope would be proposed quality criteria for whole-food animal feeding studies, and preliminary conclusions on the scientific value of such studies for GMO risk assessment. An additional agenda item will be insights from an analysis of scientific controversies around animal feeding studies including the GMO case.

 

 

Written comments, including from interested parties not able to attend, are welcome, and should be submitted before 6 April. Please, note, due to the tight schedule of the final phase of the project, this will be a firm deadline.