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SUMMARY
The authors present in this review the toxic effects of sterigmatocystin mycotoxin
in farm animals. Sterigmatocystin (STC) is a secondary metabolite of different
moulds, which is structurally closely related to aflatoxins (AF) as an intermediate
of the AF biosynthetic pathway. The most common source of sterigmatocystin
is A. nidulans and A. versicolor as these moulds are apparently unable to bio transform STC into aflatoxin B1 and G1 thus, these can contain high amounts of
STC. STC occurs mainly in grains and grain-based products due to fungal infes tation at the pre- or post-harvest stage. It has been reported in mouldy grain,
green coffee beans, spices, nuts and beer, and also cheese. Currently there are
no specific regulations or recommended maximum limits for STC in food and in
feed. It is classified as a 2B carcinogen (possibly carcinogenic to human) by the
International Agency for Research on Cancer (IARC). Liver and kidneys are the
main target organs of acute toxicity. In liver hepatocellular necrosis and haem orrhages were described. Hyaline degeneration, tubular necrosis and haemor rhages were observed in the kidneys. Results from in vivo and in vitro studies
suggest that STC may have immunomodulatory effects and it is also mutagenic
in mammalian cells. STC induces chromosomal damage both in vitro and in vivo
in experimental animals, therefore induces cytotoxicity, inhibition of cell cycle
and mitosis, as well as an increased in vivo formation of reactive oxygen spe cies and lipid peroxidation. STC forms N7-guanyl DNA adducts which are pos sibly responsible for its mutagenic effects. The toxicity of STC in livestock and
fish remains largely unknown, however, toxicity of STC has been demonstrated
in several fish species. In sheep, no signs of toxicity were observed in a feeding
trial while for other ruminants only limited data are available.
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