Mycotoxins in Horse Feed
By Ralph Robinson
Mycotoxins are formed on animal feeds when conditions of moisture and temperature allow the growth of naturally occurring molds. Mycotoxins are poisonous substances produced by molds in order to safeguard their food source (e.g., corn kernel) from a competitor - usually a bacterium. Although a few mycotoxins are “antibiotic” and used by humans (e.g., penicillin is produced by penicillin mold as a response to plant stress), most fungal toxins are damaging to animal health and contribute to liver, kidney, brain, skin, oral, gastrointestinal or reproductive toxicosis.
When horses and dogs consume lower concentrations of toxins in feed, effects are typically seen as chronic health problems. Critical quantities of toxins in feed can result in acute disease in the organs specifically targeted by the toxins.
Mycotoxicosis is dose-dependent and can cause acute disease conditions when our horses and dogs consume critical quantities of them. Specific toxins attack specific organs. In acute mycotoxicosis, the signs of disease are clear and directly referable to the affected target organs. More commonly, however, concentrations of toxins in feeds are below those that cause acute disease and at these lower concentrations, the effects of fungal toxins are seen as chronic problems, such as unthrifty growth or swollen glands, skin and coat roughness, loss of body condition, diarrhea, blood in urine, increased colic incidence, poor reproductive performance, poor athletic performance, or elevated liver enzymes on a blood panel – or maybe as a horse that is just “not right.” Fungal toxins reduce the growth rate of young animals, and some interfere with immunologic responsiveness and resistance to disease, making the horses susceptible to frequent infections. These effects on immunity and resistance are difficult to recognize because the signs of disease are associated with the infection rather than with the mycotoxin that predisposed the animal to infection.
Animals vary in their susceptibility to some mycotoxins according to the species and age of animal; young animals are generally more susceptible to certain mycotoxins than are adults. This does not imply, however, that age confers any immunity to fungal toxicosis.
As part of our on-going commitment to food safety, Herbs for Horses samples all in-coming raw materials for mycotoxins, (as well as heavy metals, certain bacteria, and pesticides) using state of the art antigen-capture technology. We also test feedstuffs on behalf of our customers. The fall harvest of 2014 shows persistent levels of the following toxins in commercial horse feeds and lower cost cereal based canine diets: Deoxynivalenol (DON) commonly known as Vomitoxin (feed refusal), Zearalenone (ZEA) (brain abnormalities), Aflatoxins (liver carcinogen), T2/HT2 (oral lesions) and Ochratoxin (nephrogenic).
Although the processing of feed ingredients does nothing to reduce any toxin burden there are compounds that can effectively sequester toxins. Some of these include certain clays, charcoal, yeast cell wall material and cellulose/hemi-cellulose/pectin.
Your veterinarian, nutritionist, or the folks at Herbs for Horses can provide you with feed testing and mycotoxin absorbents, but your first line of defence is to be self-empowered.
This article was contributed by Ralph Robinson of Herbs for Horses.
Main article photo: ©CanStockPhoto/mb fotos