Mycotoxins

Question 1

What are mycotoxins

Answer 1

Highly toxic secondary metabolites produced by fungi

Question 2

What are primary metabolites

Answer 2

Produced by all fungi as a result of normal nutrient metabolism, role in growth and development

Question 3

What are secondary metabolites

Answer 3

Not produced by all fungi, may function to establish an environmental niche against competing microbes

Question 4

Conditions for mycotoxin production

Answer 4

Having the specific gene and then specific environmental conditions which cause the gene to be expressed to lead to toxin being produced

Question 5

Can mycotoxins form pre and post harvet

Answer 5

Yes

Question 6

What is optimal moisture and why important

Answer 6

Over 13% and is most important factor in mold growth

Question 7

What are aflatoxins from

Answer 7

Aspergillus flavus

Question 8

Mechanism of toxicity from aflatoxins

Answer 8

Damage liver because aflatoxin is activated in liver to form a metabolite (epoxide) which is an oxidizing agent The epoxide binds to DNA and causes damage

Question 9

What is more sensitive to aflatoxins

Answer 9

Younger animals and monogastrics specifically birds and fish which can accumulate it over time and develop liver cancer

Question 10

What defines acute toxicity of aflatoxicosis

Answer 10

Large amount aflatoxin ingested in short time and causes clinical signs- bloody diarrhea and liver damage within hours or days

Question 11

What defines chronic toxicity of aflatoxicosis

Answer 11

Prolonged ingestion of lower amounts of the toxin causing decreased growth and liver cancer

Question 12

Diagnosis of aflatoxicosis

Answer 12

Submit feed to lab for quantitative analysis

Question 13

Treatment of aflatoxicosis

Answer 13

No antidote, just supportive care

Question 14

Zearalenone is produced by

Answer 14

Fusarium species

Question 15

Zearalenone Mimics

Answer 15

Estrogen

Question 16

Zearalenone Affects what

Answer 16

Gilts

Question 17

Zearalenone Toxicosis is causes

Answer 17

Premature sexual development or pseudo-pregnancy, low fertility, or reduce reproductive efficiency in boars

Question 18

Trichromaticthecenes do what

Answer 18

Inhibit protein synthesis by binding to ribosomes

Question 19

Vomitoxin causes what in what

Answer 19

Severe gastroenteritis with vomiting and diarrhea in pigs

Question 20

Vomitoxin treatment

Answer 20

Remove feed and check feed for others because Vomitoxin is indicator of other mycotoxins

Question 21

Fumonisins are toxic to what in body

Answer 21

hepatotoxic (liver), neurotoxic (nervous system), and carcinogenic to humans

Question 22

Fumonisin mechanism of action

Answer 22

Blocks enzymes involved production in intermediate lipid creamide of the sphingolipid (interferes with biosynthesis) in the cell membranes of liver and nerve cells

Question 23

What are signs of Equine Leukoencephalomalacia as a result of fumonisin toxicity aka moldy corn poisoning

Answer 23

Blindness, circling, staggering, seizures in horses (ruminants and poultry resistant)

Question 24

Ergot toxins are produced by

Answer 24

Claviceps purpurea

Question 25

Ergot fungi (C. purpurea) prefer what

Answer 25

Warm/wet growing seasons which favors alkaloid production

Question 26

C. Purpurea forms what

Answer 26

A sclerotia which is a structure following the germination of the fungal spore on rye, wheat, oats and others

Question 27

Ergotism clinical disease effects what mostly

Answer 27

Everything but animals that graze are mostly likely exposed, especially cattle

Question 28

What do Alkaloids do to cause symptoms of Ergotism

Answer 28

Cause vasoconstriction of arterioles to reduce blood flow to extremities- lameness is an early sign Other signs are peripheral tissue sloughing on tail, ears, and limbs in winter months

Question 29

Diagnosis and treatment of ergotism

Answer 29

Finding sclerotia in pastures or grain and need to remove food or animals from pasture, rotating crops can reduce incidence- only survives in environment for a year

Question 30

Mycotoxin detection requires what

Answer 30

To identify mycotoxin so sampling is critical and immunoassays (ELISA) will provide a rapid diagnosis

Question 31

How to manage mycotoxin in feed

Answer 31

Limit moisture post harvest, dispose of contaminated feed by burning or blend bad feed with clean feed or feed to non-susceptible species or add chelators to feed to bind toxins

Question 32

What is sensitive to Trichothecenes

Answer 32

all animal species

Question 33

Trichothecenes most prevalent mycotoxin is what

Answer 33

vomitoxin

Question 34

What animals are most sensitive to fumonisin

Answer 34

Horses and swine

Question 35

What produces fumonisin

Answer 35

Fusarium moniliforme