Aflatoxin affects all poultry species. Although it generally takes relatively
high levels to cause mortality, low levels can be detrimental if continually fed.
Young poultry, especially ducks and turkeys, are very susceptible. As a general
rule, growing poultry should not receive more than 20 ppb aflatoxin in the diet.
However, feeding levels lower than 20 ppb may still reduce their resistance to
disease, decrease their ability to withstand stress and bruising, and generally
make them unthrifty.
Laying hens generally can tolerate higher levels than young birds, but levels
should still be less than 50 ppb. Aflatoxin contamination can reduce the birds’
ability to withstand stress by inhibiting the immune system. This malfunction
can reduce egg size and possible lower egg production. In addition, one must
pay special attention to the use of contaminated corn in layer rations because
eggs are promptly used as human food and aflatoxin metabolites have been found
in egg yolks.
Mycotoxin levels found in most field situations tend to be low. Yet the combination
of low levels of mycotoxins with the stresses associated with commercial production
situations and/or exposure to disease organisms can produce effects in poultry
which are subtle, indirect, and sometimes ill-defined. Since the effects of mycotoxins
on poultry are dependent upon the age, physiological state, and nutritional status
of the animals at the time of exposure, and since mold growth at various points
within the feed production and distribution system can magnify mycotoxin problems,
mycotoxicoses can be difficult to diagnose in field situations.
Mycotoxins produced by the mold genus Fusarium include: T-2 toxin
and its chemical relatives (trichothecenes), deoxynivalenol (DON), fumonisin,
and zearalenone. Other animals tend to be more sensitive to the effects of fumonisin,
deoxynivalenol, and zearalenone when compared to poultry. Nevertheless, detection
of these mycotoxins within poultry rations indicates that the ration or the
ingredients within the ration have been subjected to mold activity. Since numerous
other mycotoxins, as well as reduced nutritive value and palatability of feeds,
are generated by mold activity, the presence of fumonisin, deoxynivalenol, or
zearalenone in poultry feeds is cause for concern.
T-2 toxin and trichothecenes can cause mouth and intestinal lesions as well
as impair the birds’ immune response, causing egg production declines,
decreased feed consumption, weight loss, and altered feather patterns. While
much is yet to be learned, T-2 toxin and related compounds are currently thought
to be most potent Fusarium mycotoxins for poultry.
DON alone has few effects in poultry. However, in field situations the DON level
is sometimes associated with reduced feed consumption in layers and broiler
breeders. This means that DON may be an indicator that T-2 or other unknown
Fusarium mycotoxins are present.
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