Aflatoxin M1 in the
feces of ewes that was confirmed by liquid chromatography/
tandem MS could be produced by the same
mechanism because ruminants possess the necessary
cytochrome P450 enzyme in the intestine but it also can
come from hepatic biotransformation and subsequent
enterohepatic circulation (Lynch, 1972; Larsson et al.,
1994; Guerre et al., 1996). Although complementary
studies will be needed to determine the origin of AFM1,
the increase in AFM1 excretion induced by YCW in the
long-term exposure in this experiment accounted for an
important proportion of the total aflatoxin eliminated
from the animal body.