Feed Section- Mycotoxins in Feed Grains
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Feed Section - Mycotoxins in Feed Grains



Current Guidelines for Mycotoxins

The Office of Indiana State Chemist (OISC) tests feeds and ingredients for mycotoxins. Testing is performed for aflatoxin, fumonisin, zearalenone, T-2 toxin and vomitoxin or DON. Animals differ in their reaction to these toxins. The FDA has established the following guidelines according to livestock specie as to the maximum toxin level that can be safely fed.

 

 

Guidance Levels for Total Aflatoxins in Livestock Feed


Class of Animal:


Feed:
Maximum Aflatoxin Level:
Immature animals and poultry
Corn & peanut products
20 ppb
Dairy animals
Corn & peanut products
20 ppb
Breeding cattle and swine
Corn & peanut products
100 ppb
Mature poultry
Corn & peanut products
100 ppb
Finishing swine over 100 lbs.
Corn & peanut products
200 ppb
Finishing beef cattle
Corn & peanut products
300 ppb
Beef cattle, swine or poultry
Cottonseed Meal
300 ppb
All animals
Other Feeds
20 ppb



Fumonisin - Fumonisin is a recently identified mycotoxin. Little published research is available relative to the safety of fumonisin. Fumonisin is known to cause equine leukoencephalomalcia in horses and pulmonary edema in pigs that eat contaminated corn. The Mycotoxin Committee of the American Association of Veterinary Laboratory Diagnosticians suggested in 1993 the following guidelines for fumonisin:


Guidance Levels for Fumonisin in Livestock Feed

Class
of Animal:

Portion
of Diet:

Maximum
Fumonisin Level:

Horses
Non-roughage portion of diet --
**Do not feed corn screenings**

5 ppm
Swine
Total ration
10 ppm
Poultry
Total ration
50 ppm
Beef cattle
Non-roughage portion of ration
50 ppm
Dairy cattle  
No recommendation


NOTE: Fumonisin can be extremely hazardous to horses. Corn screenings should never be fed to horses. When present in corn or other grains, fumonisin can result in moldy corn poisoning or leukoencephalmalcia. Common symptoms are horses become disoriented, walk aimlessly, deranged behavior, colic, press head against solid objects, blindness, and death. Horses receiving a diet containing 5 ppm fumonisin are at risk. Symptoms will develop in 7 to 35 days.  Confirmation of death resulting from equine leukoencephalmalcia requires examination of the horse's brain for pathological features including softening and liquifying of brain tissue. Prevalence of fumonisin will vary from year to year depending on weather conditions during the critical period of corn silking and ear development. Corn variety, insect damage and excess moisture during storage are also factors. A problem can be local or involve a specific storage bin or grower. Feed manufacturers selling corn or horse feed containing corn should consider conducting sufficient testing to ensure these feeds are safe for horses. The presence of fumonisin should alert feed manufacturers to monitor ingredients, especially corn, and evaluate the level of corn in horse feeds.


Vomitoxin - A toxin produced by several species of pink mold fusarium. Toxin is also known as deoxynivalenol or DON.  It is a natural toxin that forms when conditions are cold and wet where the grain is grown.   In animals, especially swine, it causes vomiting, feed refusal, immune suppression, diarrhea, weight loss, and reduced milk production. Wheat is common grain affected. Toxin may concentrate in wheat by-products. In 1995, a dog food manufacturer recalled 16,000 tons of product ($20 million loss) as a result of wheat by-product that contained >30 ppm vomitoxin. FDA has established the following guidelines:




Guidance Levels for Vomitoxin in Livestock Feed


Class of
Animal:


Portion of
Diet:

Maximum Vomitoxin Level:
Ruminating beef & feedlot cattle older than 4 months
Grain & grain by-products not
to exceed 50% of the diet

10 ppm

Chickens
Grain & grain by-products not
to exceed 50% of the diet
10 ppm

Swine
Grain & grain by-products not
to exceed 20% of the diet
5 ppm

All other animals
Grain & grain by-products not
to exceed 40% of the diet
5 ppm

 


Zearalenone - Zearalenone is another mycotoxin routinely checked by the Office of Indiana State Chemist. The critical level, that is the level considered to be unsatisfactory, is 0.5 ppm. The literature reports the effects and levels as follows; however, I haven't heard these levels as being suggested guidelines by FDA. They are, at least in the interim, something to use as a guide:

0.5 ppm may effect reproductive efficacy in young gilts 1.0 ppm may induce animal feminization 50-100 ppm can interfere with conception, ovulation, implantation, fetal development, and viability of newborn animals. 


T-2 Toxin - There is not much known about this one, however, when asked, we consider the critical level to be 0.5 ppm, based upon some North Dakota work. At the present time in Indiana, we will use the levels cited here to determine whether an assay result is to be reported as "Satisfactory" or quot;Unsatisfactory" under the Indiana Commercial Feed Law (IC15-5-13).