Mycotoxin contamination: assessment of risk in livestock systems

A desk review to assess the risk to livestock systems (pigs and ruminants) from mycotoxins was conducted by a group of researchers and veterinarians with experience of mycotoxins, cereal crops/agronomy and livestock. Information was collected from many sources – published scientific literature and grey literature/trade journals. Direct information of mycotoxin issues and other anecdotal evidence was collected from farmers and industrial sources by surveys.

The first part of this review summarises the various mycotoxins, legislation applicable to feed materials and the occurrence of mycotoxins in feed materials, as well as straw. Agronomic practices that can impact on mycotoxin levels in feed, silage, pasture and straw were reviewed and prevention strategies to minimise mycotoxin formation in the field and store were recommended.

Next, the potential effects of mycotoxins for pigs and ruminants, including dairy cattle and sheep, were considered by summarising published information on acute and chronic effects of mycotoxins on each species. Analytical testing methods, both screening and confirmatory, for mycotoxins in animal products, feed, forage straw and live animals were reviewed.

The scientific literature on the different classes of mycotoxin binders, their activity and effectiveness, was reviewed and included in this report. A substantial number of commercial mycotoxin binders/deactivators are available with suppliers offering a range of solutions from single component products to more complex, multicomponent sequestering formulations. Many producers try to provide a holistic approach towards mycotoxicosis and compensate for adverse effects. However, findings suggest that there is no sequestering product versatile enough to effectively remove low level mycotoxin mixtures from feed. Only bentonite is approved for use as a mycotoxin binder, and is approved for ruminants, pigs and poultry. Two other products approved by EFSA are biotransforming products. They each have specific activity to one type of mycotoxin, so the presence of these should be confirmed before these products are used.

Surveys of vets and farmers showed the use of binder products appears to be considerably different within the different livestock agricultural sectors. The cattle industry appears to be using binder products as part of treatment-based protocols when suspicious of mycotoxin exposure. In contrast, the use in the pig industry has much more of a prophylactic stance, often being used all year round, and primarily focussed on the adult breeding herd.

A series of key recommendation factsheets for farmers was produced. These include the need to carry out surveys of UK feed materials to determine mycotoxin levels, the need to establish more accurately animal intake of straw bedding, and research on levels of mycotoxins in pasture. Toxicity studies on lower levels of mycotoxins as well as the effects of mixtures are needed and coupled with this, there is a need to develop diagnostic analytical methods that measure biomarkers or markers of effect rather than parent mycotoxin. Finally, controlled studies on binders in real situations would be of benefit to produce conclusive evidence of their efficacy.