MYCOTOXINS

1. MYCOTOXINS • Dale M. Forsyth • Dept of Animal Sciences • Purdue University

2. MYCOTOXINS • Toxins produced by fungi • Metabolic products or by-products of fungi (molds)

3. Why Great Concern? • Some mycotoxins are DEADLY at very small dosages. • Some mycotoxins are carcinogenic. • Some mycotoxins cause huge losses in productivity in animals.

4. Most fungi do not produce Mycotoxins • Many fungi are edible • Mushrooms are fungi • Moldy feeds may be degraded without presence of mycotoxin, or may be unaffected in value. • some material courtesy of Mark Diekman

5. DIPLODIA Infested Corn

6. Effect of fungus Damage on Digestibility of Corn by Rats (Corn essentially 100% Fungus damaged) Mitchel & Beadles, 1940

7. Corn Wheat Oats Barley Recently Sorghum Cottonseed Peanut meal Rye Feeds Most Susceptible to Fungi-producing Mycotoxins

8. Moldy grain is usually nontoxic • Competition between toxic and nontoxic molds. • Entire mold population is not producing mycotoxin • Conditions for growth are different for mold growth vs mycotoxin production

9. Molds that attack grain can: • Decrease grade • Kernel damage • odor • Decrease milling quality • Decrease seed germination • Decrease dry matter • Decrease feeding value (sometimes)

10. Mycotoxins can cause: • Death • Poor performance from low FI, ADG • Respiratory problems • Reproductive problems • Liver, kidney or other organ damage • Cancer

11. MycotoxinsFactors causing variation in effects • Species, breed • Age • Sex • Nutritional status • Other diseases • Other mycotoxins • Extent of exposure

12. Some mycotoxins are formed in the field, some in storage • Storage conditions that favor production of mycotoxins: • Temperature (40 - 90o F ; 4 - 32o C) • Relative Humidity (> 70%) • Moisture (22-23% in grain) • Oxygen (1-2%)

13. MOST COMMON MYCOTOXINS in the USA • DEOXYNIVALENOL (vomitoxin) Fusarium • ZEARALENONE (Gibberella) • AFLATOXIN - Aspergillus flavus • FUMONISON - Fusarium moniliforme • ERGOT (ergotamine, dihydroergosine) Claviceps

14. Nivalenol Deoxynivalenol T-2 toxin HT-2 toxin Diacetoxyscirpenol Triacetoxyscirpendiol Fusarenone X Verrucarin A, B, J Roridin A, D, E, H Many Others (29+) These are “field” toxins, not “storage” toxins Trichothecene Mycotoxins

15. Other Mycotoxins of Growing Interest • Ochratoxins • Produced by Penicillium verrucosum and several spp. Of Asperfillus. • Potently nephrotoxic and carcinogenic, teratogenic and immunotoxic. • Public health problem, but little evidence of problematic instances in swine.

16. Other Common Molds • Penicillium • Common blue mold • Capable of producing mycotoxin, usually does not. • Diplodia • Affected cattle and sheep in Africa

17. Organisms - 1 • Fusarium • Taxonomy is quite confusing • Has had classification changed various times • Fusarium roseum, Fusarium graminearum and Gibberella zeae are all terms applied to the same thing. • Gibberella zeae is the “perfect” (reproductive) stage • Nickname “GIB” corn.

18. Fusarium toxins • Deoxynivalenol • Feed refusal • Emesis (so nicknamed “vomitoxin”) • Zearalenone • Estrogenic effects

19. Deoxynivalenol • Feed refusal factor for pigs. • Emetic (vomiting) • but seldom see pigs vomiting, refuse feed

20. Deoxynivalenol - Feed Refusal • Nearly complete refusal at low dosages (~5 ppm) by swine. • Reduced intake and poor performance at very low dosages (~1 ppm or less) • Other animals much much less affected! • DON doesn’t account for all the refusal, other metabolites are involved (though seldom tested for).

21. DON Does Not affect Reproduction

22. Field conditions that favor Gib fungus • Cool, wet weather at silking time • Slow drying weather at harvest • Varieties with tight husks

23. Recovery of DON-infected CORN • DON is very stable! • Heat, chemicals, etc. have no effect. • DON is water soluble! • So, can be leached out and washed away. • Not too practical, so • Advice: feed to other animals instead.

24. Guidelines on Levels • FDA guidelines on DON in feeds • 10 ppm in grains, by-products for chickens & cattle (5 ppm total ration) • 5 ppm in ingredients for swine max inclusion rate 20% (1 ppm total ration) • 5 ppm ingredients max inclusion 40% (2 ppm) all other animals • Canada: 1 ppm pigs, calves, lambs, lactation. • 5 ppm adult cattle, sheep, poultry

25. Zearalenone • Prepuberal gilts show enlarged, swollen vulva as if in estrus • Interrupted reproductive cycles in female swine • Prolapse of the vulva possible • Lengthened or absent estrous cycle • Little or no effect on growth

26. Little effect of Z on growth Initial wt 10 kg, fed 4 wk. James & Smith (1982)

27. Organisims - 2 • Aspergillus spp. - Especially A. flavus • Also A. parasiticus and Penicillium puberulum. • Soil organism (A. flavus), so quite common, especially in peanuts. • CAN produce AFLATOXIN • AFLATOXIN is probably the worst common mycotoxin we deal with.

28. AFLATOXIN • Most references to “mycotoxin”, unspecified, refer to Aflatoxin. • There is NO reason to assume similarities with other mycotoxins, in any regard. • Can be deadly at low dosages • In 1st outbreaks (~1960) 100,000 turkeys died + many ducks. • Associated with “groundnut” (peanut) meal

29. Aflatoxin (cont) • Occurs in corn and other grains also. • Temperature > 12 C (54 F) and high humidity (83% at 30 C). • Therefore usually a bigger problem in USA in South and Southeast. • Hepatic toxin - zonation, biliary proliferation, degeneration. • Carcinogenic in chronic situations.

30. AFLATOXIN EFFECTS • Inhibits protein synthesis • Poor gain • Liver damage • Susceptibility to Infection • Residues / carcinogenicity • Reproduction in swine not primarily affected

31. Aflatoxin on Performance

32. Aflatoxin (cont)

33. A few of many Aflatoxins

34. Aflatoxin Detection • Black Light test - BYG fluorescence • Abused. Use very carefully by trained people • Presumptive test for organism, not aflatoxin • Many other things fluoresce, including broken soybean seeds • Chromatography • Including rapid minicolumn in-field tests

35. Dealing with AFLATOXIN • FDA ACTION level is 20 ppb • Small amount may contaminate huge quantities • Strategies to decontaminate must have FDA approval in USA. • Some methods, however, can lower aflatoxin levels.

36. DECONTAMINATION • Cleaning, separation, sorting • AMMONIATION • Binding Agents • Sodium aluminosilicate and hydrated sodium calcium aluminosislicate • NOT GRAS for binding mycotoxins. • MUCH BETTER TO PREVENT FORMATION

37. Preventing Mycotoxins • Use “clean” procedures. • Prevent contamination • Inhibit mold growth • Drying • Refrigeration • Mold inhibitors

38. Additional Mycotoxins

39. FUMONISON • Deadly to horses • equine leukoencephalomalacia • Swine - pulmonary oedema • Renal toxicity and hepatotoxic

40. FUMONISON • Actually 8 analogs known, only B1, B2 & B3 often found. • ORGANISM is Fusarium moniliforme [=F. verticillioides (Sacc.) Nirenberg] or F. proliferatum • Fusarium moniliforme is VERY COMMON but seldom produces mycotoxin.

41. Fumonison - Levels • < 5 ppm for Horses • 10 ppm for swine • 50 ppm for cattle

42. ERGOT • Traditionally, this is a disease of RYE and other small grains. • New threat in Grain Sorghum (milo) to Western Hemisphere. • Has been prevalent in Africa for decades (claviceps africana) • Has very rapidly spread in last 2 years, now in USA.

43. Sorghum Ergot • Pathogen causes ovary to exude a sticky liquid. • Dihydroergosine at .6 ppm decreases FI & ADG. • Effect appears to be from poor feed intake • Dean et al, 1999

44. Traditional Ergot • Claviceps purpurea produces ergotamine and other alkaloids. • Psychoactive - convulsions, hallucinations, abortions • Paralysis, GI disturbance, gangrene of extremities, death.

45. ADVICE • Avoidance of Mycotoxin formation is best in every case • Some procedures for decontamination exist (ammonia, HSCAS), but are different for different mycotoxins, may be ineffective and may not be legal.

46. Advice- continued • I would: • Feed NO moldy feeds to reproducing animals. • Feed a small test amount to growers but DO NOT encourage consumption. • If no ill effect is observed in test, then dilute the suspect feed and incorporate small amount into normal diet.

47. WWW References to References • Australian Mycotoxin Newsletter • http://www.aciar.gov.au/aciarptp/myconews.htm • Third Joint FAO/WHO UNEP International Conference on Mycotoxins, Mar 1999 • http://www.fao.org/WAICENT/FAOINFO/ECONOMICS/ESN/mycoto/papers/