Unit 4 - Mycotoxins

Question 1

What are mycotoxins?

Answer 1

metabolites produced by a variety of fungi

Question 2

What genera are often involved with mycotoxins?

Answer 2

Aspergillus, Penicillium, and Fusarium

Question 3

What are mycotoxins most commonly a problem in?

Answer 3

cereal grains but are also observed in peanuts and other feed materials

Question 4

What are the major mycotoxins that occur in North America?

Answer 4

Aflatoxin, Zearalenone, Ochratoxin, Ergot, Trichothecenes

Question 5

What is Aflatoxin produced by?

Answer 5

Aspergillus flavus and Asperfillus parasiticus

Question 6

Where does Aflatoxin occur most commonly?

Answer 6

in the warm humid regions of the southeastern US and in irrigated regions of cotton production in the Southwest

Question 7

What does Alfatoxin cause?

Answer 7

it is hepatotoxic, carcinogenic, causes hemorrhages, slow growth, poor feed conversion

Question 8

Why is Aflatoxin a public health issue?

Answer 8

because it can accumulate in meat

Question 9

Where is Zearalenone most common in?

Answer 9

the North Central cornbeltand Southeastern Canada

Question 10

What is Zearalenone caused by?

Answer 10

Fusarium roseum

Question 11

What effects does Zearalenone have?

Answer 11

estrogenic effects, infertility, anestrus in mature sows

Question 12

Where is Ochratoxin found?

Answer 12

in Carolinas, Canada, and limited reports elsewhere

Question 13

What is Ochratoxin produced by?

Answer 13

Aspergillus ochraceus and Penicillium viridicatum

Question 14

What does Ochratoxin cause?

Answer 14

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

Question 15

What is Ergot produced by?

Answer 15

Claviceps purpurea

Question 16

What does Claviceps purpurea infect?

Answer 16

small grains such as barley, rye, and wheat primarily in the northern Great Plains

Question 17

What is Ergotism manifested by?

Answer 17

constriction of blood vessels and in high enough doses can cause gangrene of the extremities, convulsions, ataxia, and tremors - can cause agalactia in sows

Question 18

What is Neotyphodium coenophialum?

Answer 18

an endophyte fungus that produces ergovaline, an ergot alkaloid

Question 19

Where does Neotyphodium coenophialum live and how is it transmitted?

Answer 19

within the fescue plant and is not spread from plant to plant but rather transmitted through the seed

Question 20

What is ergovaline responsible for?

Answer 20

fescue root (gangrene of the extremities), summer slump, and fat necrosis

Question 21

In horses, what have ergot alkaloids associated with?

Answer 21

late-term abortions, placental thickening, retained placentas leading to infection and laminitis, prolonged gestation, difficulty re-breeding, and decreased udder development

Question 22

What are Tricothecenes produced by?

Answer 22

Fusarium roseum, Fusarium tricinctum and other members of the genus

Question 23

What is the most troubling Tricothecene toxin?

Answer 23

deoxynivalenol

Question 24

What does deoxynivalenol cause?

Answer 24

feed-refusal syndrome

Question 25

What can be done to test for mycotoxins?

Answer 25

test for mycotoxins n feed and in tissues

Question 26

How do you treat for mycotoxins?

Answer 26

it is difficult and treatment is frequently unable to reverse all effects - decreasing stress and other disease problems is better