HT-2 and T-2 in Oats - What we know and what we need to know

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1 HT-2 and T-2 in Oats - What we know and what we need to know Simon Edwards and Samuel Imathiu Harper Adams University College Shropshire, UK sedwards@harper-adams.ac.uk Hans Pettersson Swedish University of Agricultural Sciences Uppsala, Sweden Veli Hietaniemi MTT Laboratories Jokioinen, Finland Pers-Erik Clasen National Veterinary Institute Oslo, Norway Bruno Barrier-Guillot ARVALIS - Institut du végétal Boigneville, France

2 SE3 Presentation Toxicity Distribution in Europe Distribution in wheat, barley and oats Impact of agronomy on HT2 and T2 in oats Impact of processing on HT2 and T2 on oats What we need to know...

3 Slide 2 SE3 check what Keith is doing re: processing S Edwards; 12/11/2008

4 SE4 Toxicity HT2 and T2 toxins are closely related Type A trichothecenes Two of the most potent trichothecenes Have equivalent toxicity Compared to deoxynivalenol are 20-fold greater in mice and usually more than 100-fold greater to cell lines in vitro.

5 Slide 3 SE4 check what Keith is doing re: processing S Edwards; 12/11/2008

6 SE9 Toxicity The combined (HT2+T2) ttdi is 0.06 µg kg -1 bw (TDI for DON = 1 µg kg -1 bw) based on limited data (500-fold safety factor) SCOOP Task estimated ttdi exceeded in many cases However Low incidence and high LoD resulted in high proportion of estimated exposure based on content of samples with no detectable HT2 or T2

7 Slide 4 SE9 check what Keith is doing re: processing S Edwards; 12/11/2008

8 Distribution in Europe Surveys conducted in Nordic countries in early 1990s More recent survey conducted in Nordic countries, UK and France Indication that increasing levels in oats Indication that some countries have some incidence on barley and maize, limited incidence in wheat

9 Increasing HT2 + T2 concentration in Northern European Oats

10 Different mycotoxin profile cereals (2007) % > 50 ppb HT2+T2 Wheat Barley Oats UK Norway Finland Sweden 0-91 France 3 29 (Spring) -

11 UK Conventional Oats highest reported HT2 and T2 HT2+T2 concentration (ppb) Year Sample No. %>10ppb Mean Median 90th% 95th% Max Conventional samples higher than organic Some variation between years but high concentration in all years

12 Distribution of HT2 and T2 in UK oats ( )

13 SE7 Correlations between Type A trichothecenes UK oats Good correlations between HT2 and T2, T2 triol and neosolaniol

14 Slide 10 SE7 check what Keith is doing re: processing S Edwards; 12/11/2008

15 SE8 Correlations between Type A and Type B trichothecenes UK oats No correlation between HT2 and deoxynivalenol or nivalenol Evidence of mutual exclusion Same pattern seen in UK wheat and barley

16 Slide 11 SE8 check what Keith is doing re: processing S Edwards; 12/11/2008

17 Statistical analysis To determine the effects of agronomic factors on the fusarium mycotoxin contamination of cereals For HT2 and T2 in UK oats: Multicolinearity within model Not suitable to predict risk

18 Multicolinearity within model Model split into two main groups: Conventional oats Most follow wheat or barley Most grow variety Gerald Organic oats Most follow non-cereals Most grow other varieties Model identified previous crop, variety and other differences between conventional and organic were all significant Need controlled field experiments to determine relative impact of different agronomic factors on mycotoxin content of oats

19 Analysis of UK oats by year and region HT2+T2 in oats DON in wheat

20 Organic and conventional UK oats Oats Much lower levels in organic oats Wheat No significant difference HT2+T2 in Oats DON in Wheat

21 Oat varietal differences to HT2+T2 content Differences maybe genetic or agronomic

22 Oat varietal differences to HT2+T2 content Differences between winter varieties likely to be genetic Little difference between spring varieties

23 Impact of Agronomy Different situations for different cereal crops DON and zearalenone in wheat seasonal and regional differences mass of information codes of practice available risk assessments available HT2 and T2 in oats little regional differences, some seasonal differences very limited information codes of practice not directly applicable no risk assessment available

24 Impact of Processing Majority of trichothecenes in outer hull (husk) All oats are de-hulled for human consumption Reductions of >90% consistently achieved Mycotoxins concentration very high in the pelleted byproduct used for animal feed

25 Fusarium infection of oats Fusarium on oats (panicle blight) not perceived as an important disease HT2+T2 detected in oats in mid-1990 s in Norway New species identified on oats which could produce HT2 and T2, named Fusarium langsethiae in 2004 Very limited information available about this species

26 Fusarium langsethiae Distinct colony morphology Slow growing easily outgrown by other fungi

27 Identification of Fusarium in UK oats Microbiological examination of oats with high HT2 and T2 found F. langsethiae, and no other HT2+T2 producing species DNA-based quantitative PCR developed to quantify F. langsethiae in oat material. Regression analysis indicates strong relationship between F. langsethiae DNA and HT2 and T2 concentration. PCR analysis has failed to detect other HT2+T2 producing species in UK oats. Species responsible for HT2 and T2 identified as Fusarium langsethiae in UK oats

28 Regression of HT2+T2 against F. langsethiae DNA 240 oat samples

29 Regression of HT2+T2 against F. langsethiae DNA 120 single seeds

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31 Need for research funding COMMISSION REGULATION (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs Para 31 Intake estimates indicate that the presence of T-2 and HT-2 toxin can be of concern for public health. Therefore, the development of a reliable and sensitive method, collection of more occurrence data and more investigations/research in the factors involved in the presence of T-2 and HT-2 toxin in cereals and cereal products, in particular in oats and oat products, is necessary and of high priority.

32 What we need to know What is metabolic fate/toxicity of HT-2 and related type A trichothecenes? (Recent surveys have found T2 tetraol concentration to be higher than T2) What are consumption levels? (Need extensive surveys of cereal products with sensitive methods and/or monitoring of biomarkers) What meteorological factors dictate seasonal distribution of HT2 and T2 in cereals? Why are there differences between countries? Why are there differences between cereals hosts? How do agronomic factors impact on the HT2 and T2 content of cereals? How and when does Fusarium langsethiae infect cereals? How can we artificially inoculate oats? (need to conduct experiments) What varietal traits result in susceptibility/resistance to Fusarium langsethiae? Do fungicides control Fusarium langsethiae?

33 Acknowledgements Hans Pettersson Swedish University of Agricultural Sciences Uppsala, Sweden Veli Hietaniemi MTT Laboratories Jokioinen, Finland Pers-Erik Clasen National Veterinary Institute Oslo, Norway Bruno Barrier-Guillot ARVALIS - Institut du végétal Boigneville, France View expressed are my own and may not be those of my colleagues and/or funding bodies