Mycotoxins

Effects of Mycotoxins on Swine Health and Productivity

Swine are sensitive to mycotoxins, especially nursing or nursery-age swine. In general, mycotoxins cause reductions in feed intake, growth performance, and immune function when levels are relatively low. Producers must be aware that if one toxin is identified in a sample, the chances are high that other toxins are present. Some toxins may not have been identified as of yet, but research on known mycotoxins provides insight into the expected effects in swine and potential methods to reduce those effects. Table 3 contains a summary of the maximum permissible concentrations of mycotoxins in swine feeds.

Aflatoxin B1 has been the most extensively studied. Twenty to 200 ppb will cause a decrease in feed intake and growth performance, which can be partially offset by increasing specific dietary nutrients such as lysine or methionine. In severe cases (1,000 to 5,000 ppb) of aflatoxicosis, one can expect acute effects including death. Aflatoxin M1 appears in milk of sows consuming aflatoxin-contaminated diets and may affect piglets nursing those sows.

Feed concentrations of deoxynivalenol (DON) of 300 to 500 ppb are often associated with feed refusal, decreased weight gain, and increased incidence of infectious diseases. DON levels greater than 1000 ppb, will cause feed refusal or decrease in feed intake resulting in severe weight loss. It appears that pigs will often consume a sufficient amount of contaminated feed to induce vomiting. In fact, DON is also called vomitoxin because of its association with swine vomiting.

T-2 toxin has detrimental effects on swine performance, but no effect levels have not been determined for commercial production environments. However, field observations indicated that T-2 and related compounds are associated with decreased productivity at feed concentrations of 200 ppb or less.

Zearalenone will significantly affect the reproductive performance of swine. Prepuberal gilts are the most sensitive to zearalenone. The symptoms commonly observed when feeding diets contaminated with zearalenone include a reddening and increased size of the vulva, and increased size of mammary tissue. Zearalenone will cause embryonic mortality at certain stages of gestation. Fertility problems are often associated with zearalenone concentrations of 100 to 200 ppb in sow feeds.


     Table 3.  Maximum Mycotoxin Levels for Swine

                                Maximum Dietary Concentration    


             
                           Deoxynivalenol  Zearalenone  Aflatoxin
         Swine Type              ppb           ppb          ppb  
         
         Pigs <75 lb            <300           200          
20
         Pigs 75 to 125 lb      <300           200           50
         Pigs 125 lb to market  <300           200          100
         Sow Herd               <300           100           50
         Breeding Males         <300           100           50
         
These levels are based on extensive field observations.
          
Heat stress, marginal nutrient plane, crowding, disease exposure,
the presence of more than one mycotoxin, and drug interactions,
as well other factors, increase animals' susceptibility to
mycotoxins. Thus these recommendations must be tempered with
knowledge of the animals involved.

Prepared by

Mary Beth Genter, Extension Toxicology Specialist
Winston M. Hagler, Director of NCSU Mycotoxin Laboratory
Jeff A. Hansen, Extension Animal Science Specialist
Bob A. Mowrey, Extension Animal Science Specialist
Frank T. Jones, Editor, Extension Poultry Science Specialist
Matt H. Poore, Extension Animal Science Specialist
Lon W. Whitlow, Extension Animal Science Specialist

http://www.ces.ncsu.edu/gaston/