Mycotoxins in Animal Feeds

Background:  Due to the unseasonably wet weather and delayed harvest of grain, conditions have been favorable for mold growth in corn crops throughout the state.  Corn ear molds, particularly Giberella and Fusarium molds, have been reported throughout Indiana at levels that have not been observed in the state for decades.  The persistence of these molds in the corn crop is a concern due to the potential of these fungi to produce mycotoxins.  Mycotoxins are naturally-occurring, secondary metabolites produced by a variety of molds and can be toxic to animals and livestock.  In Indiana, the mycotoxins of major importance include aflatoxin, deoxynivalenol (also known as DON or vomitoxin), fumonisin, and zearalenone.  Giberella and Fusarium molds can appear red or pink in color (and occasionally white) and can potentially produce deoxynivalenol, zearalenone, and fumonisin.   Aspergillus molds are typically yellow-green in color and can produce aflatoxin.

  Since August 2009, the Indiana Animal Disease Diagnostic Laboratory has detected significant amounts of deoxynivalenol, fumonisin, and zearalenone in corn/grain samples.  The approximate concentrations detected for these mycotoxins range from 1-40 ppm for deoxynivalenol, 2-70 ppm for fumonisin, and 1-10 ppm for zearalenone.  For information on  the action/guidance levels for these mycotoxins in livestock feed, see tables 1-4 below.  It is important to remember that observation of mold on corn or other grain does not necessarily mean that mycotoxins are present.  Therefore, it is important that the corn or grain is submitted for laboratory testing in order to assess the presence of mycotoxins in suspect samples.

-by Dr. Christina Wilson, Head of Toxicology/Analytical Chemistry

Table 1.  Action Levels for Total Aflatoxins in Livestock Feed

Table 2.  Guidance Levels for Total Fumonisins in Animal Feeds

*Includes lactating dairy cattle and hens laying eggs for human  consumption
**Dry weight basis

Table 3.  Advisory Levels for Vomitoxin (DON) in  Livestock Feed

Table 4.  Minimum Levels of Zearalenone Associated with Clinical Signs in Animals

References:

1. Wise K and Woloshuk K: 2009.  Corn Ear Rots Widespread in Indiana. Pest & Crop 26:1-2.

2. Marasas WFO and Nelson PE: 1987.  Hemorrhagic Syndrome.  In: Mycotoxicology: Introduction to the Mycology, Plant Pathology, Chemistry, Toxicology, and Pathology of Naturally Occurring Mycotoxicoses in Animals and Man.  The Pennsylvania State University Press, University Park, PA.  pp 41-43.

3. Marasas WFO and Nelson PE: 1987.  Estrogenic Syndrome.  In: Mycotoxicology: Introduction to the Mycology, Plant Pathology, Chemistry, Toxicology, and Pathology of Naturally Occurring Mycotoxicoses in Animals and Man.  The Pennsylvania State University Press, University Park, PA.  pp 45-48.

4. Marasas WFO and Nelson PE: 1987.  Feed Refusal and Emetic Syndromes.  In: Mycotoxicology: Introduction to the Mycology, Plant Pathology, Chemistry, Toxicology, and Pathology of Naturally Occurring Mycotoxicoses in Animals and Man.  The Pennsylvania State University Press, University Park, PA.  pp 65-67.

5. Marasas WFO and Nelson PE: 1987.  Equine Leukoencephalomalacia.  In: Mycotoxicology: Introduction to the Mycology, Plant Pathology, Chemistry, Toxicology, and Pathology of Naturally Occurring Mycotoxicoses in Animals and Man.  The Pennsylvania State University Press, University Park, PA.  pp 69-72.

6. Maracas WFO and Nelson PE: 1987.  Aflatoxicosis. In: Mycotoxicology: Introduction to the Mycology, Plant Pathology, Chemistry, Toxicology, and Pathology of Naturally Occurring Mycotoxicoses in Animals and Man.  The Pennsylvania State University Press, University Park, PA.  pp 25-31.

7. Henry MH: 2006.  Mycotoxins in Feeds: CVM's Perspective.  Presentation for Risk Management Agency, Austin, TX.

8. Osweiler GD: 1996.  Zearalenone.  In: Toxicology, The National Veterinary Medical Series.  Williams & Wilkins, Media, PA.  p. 421.