Unit 4 - Mycotoxins Flashcards
What are mycotoxins?
metabolites produced by a variety of fungi
What genera are often involved with mycotoxins?
Aspergillus, Penicillium, and Fusarium
What are mycotoxins most commonly a problem in?
cereal grains but are also observed in peanuts and other feed materials
What are the major mycotoxins that occur in North America?
Aflatoxin, Zearalenone, Ochratoxin, Ergot, Trichothecenes
What is Aflatoxin produced by?
Aspergillus flavus and Asperfillus parasiticus
Where does Aflatoxin occur most commonly?
in the warm humid regions of the southeastern US and in irrigated regions of cotton production in the Southwest
What does Alfatoxin cause?
it is hepatotoxic, carcinogenic, causes hemorrhages, slow growth, poor feed conversion
Why is Aflatoxin a public health issue?
because it can accumulate in meat
Where is Zearalenone most common in?
the North Central cornbeltand Southeastern Canada
What is Zearalenone caused by?
Fusarium roseum
What effects does Zearalenone have?
estrogenic effects, infertility, anestrus in mature sows
Where is Ochratoxin found?
in Carolinas, Canada, and limited reports elsewhere
What is Ochratoxin produced by?
Aspergillus ochraceus and Penicillium viridicatum
What does Ochratoxin cause?
it is primarily nephrotoxic and in acute exposure it can lead to kidney failure and death - it is also hepatotoxic, can cause enteritis, immune suppression emaciation, and dehydration
What is Ergot produced by?
Claviceps purpurea
What does Claviceps purpurea infect?
small grains such as barley, rye, and wheat primarily in the northern Great Plains
What is Ergotism manifested by?
constriction of blood vessels and in high enough doses can cause gangrene of the extremities, convulsions, ataxia, and tremors - can cause agalactia in sows
What is Neotyphodium coenophialum?
an endophyte fungus that produces ergovaline, an ergot alkaloid
Where does Neotyphodium coenophialum live and how is it transmitted?
within the fescue plant and is not spread from plant to plant but rather transmitted through the seed
What is ergovaline responsible for?
fescue root (gangrene of the extremities), summer slump, and fat necrosis
In horses, what have ergot alkaloids associated with?
late-term abortions, placental thickening, retained placentas leading to infection and laminitis, prolonged gestation, difficulty re-breeding, and decreased udder development
What are Tricothecenes produced by?
Fusarium roseum, Fusarium tricinctum and other members of the genus
What is the most troubling Tricothecene toxin?
deoxynivalenol
What does deoxynivalenol cause?
feed-refusal syndrome
What can be done to test for mycotoxins?
test for mycotoxins n feed and in tissues
How do you treat for mycotoxins?
it is difficult and treatment is frequently unable to reverse all effects - decreasing stress and other disease problems is better
