Aflatoxin can, however, occur in corn and other grains when growing conditions are hot and dry. Aflatoxin is a toxic product, causing liver damage, reduced growth, and feed conversion at levels above 100 ppb. It can be carcinogenic, and FDA regulates the maximum dietary level at 20 ppb. Because of the very strong feed refusal response which DON elicits, pigs are seldom seen vomiting. The pig seems to be more sensitive to the presence of this mycotoxin in feed than other livestock species.
Starvation is the condition usually observed.
Poor performance associated with poor feed intake occurs above a dietary level of 1 ppm. Zearalenone is produced by the same organism as DON but usually is formed under different conditions. Zearalenone consumption will produce vulva swelling, prolapse, pseudopregnancy, false heat symptoms, and other estrogenic problems in the reproductive process. The organism that produces DON and zearalenone has been a source of confusion in taxonomy, and its name and classification have been changed more than once. Fusarium roseum is now the accepted name, but a particular stage of the organism, Gibberella zeae , produces the toxins and has been used by many to avoid some of the confusion with other terms.