Mycotoxins and mycotoxicosis in livestock production by Francisco J. Martínez and Fernando Aguado, Export Department, Nufoer SL, Madrid, Spain Cereal and cereal by-products, corn grains and corn silage are thought to be the most exposed ingredients to mould and mycotoxin contamination. This article by Francisco Martinex and Fernando Aguado at Nufoer
SL in Spain looks at the major mycotoxins and why it is important to test for an array and not for a single one in order to analyse feed quality and risks
ycotoxicosis refers to the different diseases caused by exposure to different mycotoxins, and it has a high occurrence in livestock production. Mycotoxins are fungal secondary metabolites, toxic to humans and animals, produced by certain species of fungus. The growth capacity of these fungi depends on several environmental factors such as moisture, temperature and availability of energy and nitrogen sources. Likewise, the production of mycotoxins depends on specific environmental factors, and the presence of mycotoxigenic fungi does not imply a presence of mycotoxins and vice versa, since mycotoxins present great stability and can be present in feedstuffs even after the deterioration of the producing fungus. Cereal and cereal by-products, corn grains and corn silage are thought to be the most exposed ingredients to mold and mycotoxin contamination, depending on various factors such as grain handling, processing and storage conditions.
38 | Milling and Grain
Mechanically damaged grain seeds are more prone to mold contamination than intact ones. Storage facilities with high moisture content (above 13 – 15 percent) and high temperatures (above 25–27ºC) facilitate mold growth and contamination of grain. Depending on the feed contamination level, exposure, environmental factors, mycotoxin, fungal species and animal species involved, the clinical symptoms may differ. However, mycotoxins rarely occur at concentrations high enough to cause clinical symptoms: mycotoxins are more frequently present in animal feed at low concentrations, producing subclinical symptoms over a long period of time, which are more difficult to diagnose and are of greater economic importance (Marquardt, 1996; Bryden, 2004). It is important to emphasize that mycotoxicosis are often owed to the action of several mycotoxins ingested by the animals. Indeed, different mycotoxins can occur simultaneously in feedstuffs, since some mycotoxigenic fungi are known to produce different kinds of mycotoxins, and feed raw materials are commonly contaminated with different fungi species at a time (Bottalico, 1998; Sweeney et al., 1998). In addition, a large number of studies have shown toxicological interactions between different mycotoxins, ranging from synergistic to antagonistic interactions (Grenier et al., 2011; Mallmann et al., 2011). Therefore, it is important to test for an array of mycotoxins and not for a single one in order to analyze feed quality and risks.
Major mycotoxins in animal feed
There are over 300 mycotoxins discovered, but the main mycotoxins classes of concern in animal and human health are produced mostly by species of genus Aspergillus, Fusarium and Penicillium. In the European Union context, only a few of these mycotoxins (aflatoxins, fumonisins, deoxynivalenol, zearalenone and ochratoxin A) are subjected to legal regulations setting