Mycotoxins and animal health: an ongoing challenge

16-11-2010 | |

Mycotoxins remain an ongoing challenge for the animal and human health industry, according to several experts speaking at the World Mycotoxin Forum, a 3 day event held in the Netherlands.

Christopher Wild from the International Agency for Research on Cancer in France explained in his plenary session that mycotoxins are a largely ignored global health problem. In the economically wealthier parts of the world mycotoxins exposure is controlled or minimised by regulation and surveillance.
However, in other parts of the world such as Africa, such protection is lacking. Wild explained that the high exposure of aflatoxins in West Africa increases the risk of developing liver cancer, reduces growth and immune suppression in young children.
Metabolic disturbances
Prof Dr Wayne Bryden, University of Queensland in Australia, said that mycotoxin contamination levels in feedstuffs are usually not high enough to cause an overt disease.
However, low level toxin ingestion may cause an array of metabolic disturbances resulting in poor animal health.
These disturbances are often difficult to recognise because signs of the disease are associated with infection rather than with the toxin that predisposed the animal to infection; making a diagnosis of a mycotoxicosis difficult.
Gene profiling
In her presentation, Prof Dr Johanna Fink-Gremmels from Utrecht University in the Netherlands delved into the signature of mycotoxicosis: gene profiling.
In the area of mycotoxin research, gene expression analysis is widely used in the elucidation of the biosyntethic pathways of individual mycotoxins and factors that influence the structure and amount of a mycotoxin produced by one or more fungal species.
Gene expression analysis can be a good approach to present biomarkers of effect when animals are exposed to more than 1 mycotoxin at the same time (which is often the case).
Results of a first series of experiments in cattle seem to be promising, explained Fink-Gremmels.
Mycotoxin cocktail
Bertrand Grenier from the French National Institute for Agricultural Research (INRA) also underlined the fact that animals are often exposed to a cocktail of mycotoxins. The mycotoxins interact which other, explained Grenier.
Trials have showed the most interaction between aflatoxin and ochratoxin A, aflatoxin and fumonisin and moniliformin, aflatoxin and T2 toxin and ochratoxin A and citrinin.
Grenier explained that combinations of mycotoxins at low concentrations of individual mycotoxins may have negative effect on animal health. At the same time, current legislation and recommendations are based on individual mycotoxins and not multi-contamination.
Masked mycotoxins
Prof Dr Sarah De Saeger from Ghent University in Belgium talked about challenges to combat masked mycotoxins.
She explained that masked (or conjugated) mycotoxins first caught attention in the late 1980s because in some cases of mycotoxicosis, clinical observations in animals did not correlate with the low mycotoxin content determined in the feed.
The unexpected high toxicity was therefore attributed to the occurrence of undetected, conjugated forms of mycotoxins that possibly hydrolyse to the precursor toxins in the digestive tract of animals.
But the research on masked mycotoxins has exponentially grown explained De Saeger. Different research groups are now focusing on the variety of masked mycotoxins, the occurrence, bioavailability and toxicity of the masked forms among others.(Emmy Koeleman)

Dick Ziggers Former editor All About Feed
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