Mycotoxins in Swine: A Complete Overview

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Key Facts

  • Mycotoxins in feed can have negative impacts on pig performance and health.
  • There are three major mycotoxins that affect pigs: vomitoxin (DON), zearalenone (ZER), and T-2 toxins.
  • The presence of different mycotoxins or combinations of mycotoxins require different strategies to manage and mitigate effects on performance of pigs.

What are mycotoxins?

Fungi, also known as moulds, live and grow on feedstuffs when conditions are favourable. Some, but not all, moulds produce toxins that can cause disease in livestock and poultry. These toxins are referred to as mycotoxins. Over 200 different types of mycotoxins have been identified. In Ontario, there are three major mycotoxins that are relevant to pigs: vomitoxin, zearalenone, and T-2 toxins.

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Vomitoxin (deoxynivalenol or DON) is the most common type of mycotoxin and is associated with feed refusal in pigs. The reduction in feed intake is proportional to the concentration of the toxins in the diet. The reduction in growth rate and feed conversion of pigs is primarily due to a reduced intake of essential nutrients. At high concentrations in the diet, DON also causes vomiting in pigs.

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Zearalenone (ZER) is most commonly produced with alternating temperatures during grain maturation. It mimics the action of estrogen, a key reproductive hormone, and can therefore limit reproductive performance. In gilts and sows, the vulva and reproductive tract become enlarged and vaginal and rectal prolapses occur. Heat timing becomes irregular and litter size is reduced. Market animals may show signs of increased irritability, causing tail biting and fighting. Growth decline in market weight animals can also occur.

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Other Trichothecenes (T-2)

T-2 toxins are less prevalent in Canadian grains and are produced under conditions of alternating temperatures and over-wintered crops. These toxins are far more damaging than DON, causing nervous disorders, irritation of the skin and digestive tract, birth defects, reduced disease resistance, and hemorrhaging in addition to decreased feed intake.
How do I interpret my grain results?

It is difficult to predict mycotoxin results’ impact on pig performance. The method for sampling is critical, as it is widely recognized that the mycotoxin is not evenly distributed within the field and the grain lots and samples may not be representative. There may be other (untested) toxins present and synergies between toxins can also occur.

Managing toxins in your feed

Several strategies can be used, either singularly or in combination, to mitigate the negative impacts of consuming mycotoxin-contamination grains.


The severity of the effects mycotoxins have on your herd is directly related to their level in feed. At low to moderate levels, diluting contaminated grain with clean grain is the first option to consider. If you are unable to dilute your contaminated grain due to bin restrictions or storage requirements, Shur-Gain/Trouw Nutrition can make a custom supplement based on our precision feeding models and your mycotoxin results and help to alleviate the negative impact of highly naturally tainted grains.

Increase diet nutrient density

As a result of decreased feed intake, the intake of essential nutrients is not sufficient to support maximum growth rate. By increasing the nutrient density of the diet, both energy and nutrient intake can be maintained while the intake of mycotoxin-contaminated grain is reduced.

For additional information, contact your Swine Nutrition Advisor.