Aflatoxins in feed: ongoing challenge

Aflatoxins (AF), secondary metabolites of some species belonging to Aspergillus section Flavi, present a high health hazard for humans and animals. The contamination of plant materials, mostly seeds, can occur in field or during any phase of post-harvest process and storage. After the ingestion, aflatoxins can be transmitted along the food chain either unchanged or metabolised in other more or less toxic forms. In mammalians, for example, AFB1 is metabolized in AFM1 secreted in milk. The concentration of these toxins in food and feed commodities is limited by law in almost all countries. Feed contamination by aflatoxins can cause severe economical damages to growers due to impaired animal growth, immune depression and consequent possibility of major exposure to infectious illnesses as well as animal products not conformed to the official food safety standards. Different strategies, either prevention or detoxification, have been applied to control the presence of aflatoxins in food and feed but none of them has completely solved the problem. Oxidative stress in fungal cell is considered a prerequisite for aflatoxin synthesis. Moreover the presence of lipoperoxides on the commodities contaminated with the aflatoxigenic fungi enhances toxin production. Different antioxidants are used in a prevention strategy to control the presence of aflatoxins in food and feed. An example of control strategy is application of adsorbents, clays or microorganisms, for removal of ingested aflatoxins in animal rumen. The research of new, more environmentally friendly strategies and tools in aflatoxin control is still ongoing.