The late harvest of a record corn crop in 2009, along with that year's adverse weather, has increased the odds that certain mycotoxin-producing moulds may be present in the feed grain. But according to the Poultry Science Association (PSA), poultry farmers can greatly reduce concerns about exposing their flocks to these toxic substances through proper testing at their feed facilities.

Mycotoxins are produced by some types of moulds and fungi and can be toxic to both humans and animals. After attacking a grain such as corn, some moulds produce mycotoxins either in the field, prior to harvest, or later, during storage, when storage conditions are favourable to their development. The US carefully monitors mycotoxins to limit their presence in the human food supply; however, their appearance in feed can cause loss damages to farm animal producers, including poultry farmers.

According to PSA member Dr Frank Jones, a recently retired professor and extension specialist from the Center of Excellence for Poultry Science at the University of Arkansas, because most corn farmers do not test their own grains for mycotoxins, it is incumbent on poultry producers to do their own testing at their feed facilities – and to do so in an accurate and cost-efficient way.

Testing for Mycotoxins Produced by Fusarium Moulds

According to Dr Jones, this year's mycotoxin-related problems are being caused by Fusarium, a group of moulds that are pathogenic to corn plants, causing ear rot and other diseases in corn. They also produce mycotoxins. After invading the ear, some Fusarium moulds are capable of producing up to 17 different mycotoxins at once.

Fortunately, according to Dr Jones, there is a way for poultry farmers to avoid the time and expense of testing for all 17.

He explained: "The most common type of mycotoxin produced by Fusarium is DON (deoxynivalenol – also known as vomitoxin). Because of its prevalence, DON should be used as an indicator of whether their might be a larger problem with any load of grain a poultry farmer is considering for purchase,

"While DON itself is not particularly toxic to poultry, finding it in a test sample is an excellent indication that other potentially harmful toxins may be present. And testing only for DON is much more cost-effective than doing separate tests for each of the large variety of possible mycotoxins."

The Importance of Proper Sampling

However, test results are only as good as the samples provided.

According to Dr Jones, 85 to 90 per cent of errors in analysis come from poor sampling. To avoid errors, he said, poultry farmers should collect and grind a ten-pound sample of the corn. The grinding ensures that any contaminated kernels will be blended into the entire sample – a process simulating what will happen in the grain mill itself.

A one part per million prevalence of DON should be used as the cut-off point for using the grain, with ratios any higher than that being rejected, according to Dr Jones.

Use of Suspect Grains

If a poultry farmer must use grains suspected of harbouring low levels of mycotoxins, then they should be fed only to birds over three weeks of age because, according to Dr Jones, mycotoxins tend to affect younger animals before they affect older ones.

Poultry farmers should avoid having any mycotoxins present in their withdraw feeds – usually the last week of feed.

Dr Jones concluded: "Fortunately, we can now detect mycotoxins in meat at the level of parts per quadrillion – roughly equivalent to detecting a drop of alcohol from a single fifth of whiskey mixed into all the oceans in the world – so the odds of mycotoxins reaching and harming consumers through meat products are extremely small.

"However, mycotoxins can cause a number of harms to poultry farmers' flocks, including negatively impacting birds' immune systems and specific organs, which can lead to higher incidence of disease. They can also reduce egg production, decrease feed utilisation and efficiency, and increase the prevalence of jaundice, anaemia and embryonic death.

"So taking every possible step to minimise the presence of mycotoxins in feed is vitally important to running both a safe and cost-effective operation."

February 2010