The susceptibility of poultry to the negative effects of mycotoxin ingestion have been known for more than 50 years, ever since the "Turkey X Syndrome" outbreak in 1960 was traced to the presence of the Aspergillus spp. mycotoxin aflatoxin (AFB1) in turkey feed.

Since then, many additional mycotoxins have been identified, and the potential threat to poultry health and production has become well accepted globally.

For the poultry industry, AFB1 remains the greatest threat, with poultry more susceptible to AFB1 ingestion than any other livestock species.

As evidence of this clear difference in vulnerability has mounted, so too has the demand for solutions to the mycotoxin problem that target the specific threat and physiological differences of each individual species.

Identifying mycotoxin threats

Of primary concern to poultry producers are the mycotoxins produced by Aspergillus spp., which regularly develop during the storage of feeds and feed ingredients, as well as infecting growing crops.

In addition to AFB1, the ochratoxins (OTA) are also highly toxic for poultry. This is in stark contrast to pigs, for example, which are at greatest risk from mycotoxins produced by Fusarium spp. fungal diseases, such as deoxynivalenol (DON), zearalenone (ZON), fumonisin (FUM) and T2 toxin.

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Of primary concern to poultry producers are the mycotoxins produced by Aspergillus spp., which regularly develop during the storage of feeds and feed ingredients, as well as infecting growing crops.

However, commercially produced poultry in modern production units can still be exposed to considerable levels of Fusarium spp. mycotoxins in feed due to the heavy reliance on cereal grains.

In a survey of poultry diets from across Europe, the Middle East and Russia carried out by Micron Bio-Systems between 2014 and 2015, 96-97 percent of samples contained DON, FUM and ZON, with DON in particular found at extremely high levels that averaged more than 900 parts per billion.

Although no AFB1 or OTA were found in these particular samples, the risk may be higher in other regions of the world.

It is also worth remembering that poultry diets rely heavily on human-edible ingredients – the more stringent mycotoxin limits for human consumption mean that rejected food batches often find their way into poultry feed. 

Impact on poultry performance

The effects of these mycotoxins on poultry health and performance vary considerably (Figure 1).

AFB1 is a carcinogenic compound that is known to affect gene regulation and metabolism at the cellular level, the symptoms of which include liver damage, development of fatty liver, immune suppression and reduced growth rates. In contrast, OTA is associated with renal dysfunction and kidney damage, and is reported to affect weight gain, feed intakes and immune function. Both can cause increased mortality where levels of exposure are high.

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The effect of mycotoxins on poultry health and performance varies considerably, with aflatoxin in particular being a carcinogen known to affect gene regulation and metabolism at the cellular level.

Although poultry are considered relatively resistant to the Fusarium spp. mycotoxins, the potential threat should not be overlooked completely, because the possible negative effects of ingestion have not been as extensively researched as those for AFB1 or OTA. Ingestion of ZON in particular, which is an estrogen mimic, may affect fertility and egg production in breeder and layer units.

In addition, even low levels of DON – the mycotoxin most frequently found in feed – and T2 toxin are known to damage the lining of the small intestine and reduce nutrient absorption. This has the potential to negatively affect feed conversion efficiency, feed intakes and liveweight gain. Along with FUM, these mycotoxins also impair immune function, increasing susceptibility to disease.

Poultry-specific challenges

This potential impact on immune function is critical in poultry, with the breeder stage of the production cycle perhaps the most important when it comes to managing the risk of mycotoxin ingestion.

This is due to the fact that, in addition the direct effects on breeders, which include increased embryonic mortality and diarrhea, plus reduced hatchability, feed intakes and body weight gain, the consumption of contaminated poultry feed by breeders can cause immune dysfunction, reduced body weight and abnormalities in their progeny.

Poultry producers also need to consider the role that mycotoxins may play in intestinal disorders. There is evidence to suggest that some mycotoxins can pre-dispose poultry to other diseases, such as Clostridium perfringens-induced necrotic enteritis and coccidiosis, with subsequent negative effects for growth rates, feed conversion and mortality.

Mycotoxin remediation strategies

With these mycotoxin threats now widely recognized, the use of in-feed mycotoxin deactivators and binders has increased markedly in recent years. Designed to bind, transform or degrade mycotoxins, there is a wide range of such products available commercially.

Binding (adsorption) is the most common approach within the feed industry, with clay minerals such as bentonite used to bind with polar mycotoxins (AFB1) and yeast cell walls demonstrating some efficacy against non-polar Fusarium spp. mycotoxins. The ability to maintain efficacy within the pH range typically found in the bird’s gastrointestinal tract (pH 3-7) is critical to success, and can vary considerably between different binders.

An additional strategy, particularly for non-polar mycotoxins, is to remove or modify a particular functional site on the surface of the mycotoxin. This transformation can render the mycotoxin harmless, or expose the binding site of the molecule to mineral binding agents.

Finally, degradation is the application of multiple transformations to ensure that any mycotoxin fragments remaining after transformation – even if bound to a mineral binder – do not retain any toxic effect.

For poultry producers, the strategy of transformation and degradation is critical, becauseit is the most effective in eliminating the effects of DON, which is one of the most prevalent mycotoxins in poultry feeds.

Targeted poultry solutions

The most effective approach is typically a combination of all three strategies and the specific nature of the mycotoxin threat that will dictate how such strategies should be prioritized.

Although reliant on effective and timely testing of feed samples for actual mycotoxin loading, the recent development of species-specific in-feed mycotoxin solutions is a major advance in mycotoxin remediation, and is leading the way toward potential customized, bespoke solutions based on individual farm mycotoxin profiles.