Mycotoxins

Question 1

Mycotoxins Characteristis

Answer 1

Non-antigenic, heat-stable metabolites of filamentous fungi [plant pathogens]
Produced by fungi growing on crops or in stored feed

Question 2

Mycotoxins

Predisposing factors

Answer 2

Availability of usable substrate
Ambient temperature [20oC to 30oC]
Moisture
Damage by insects and harvesting machines

Question 3

Mycotoxicoses

Answer 3

Diseases associated with fungal toxin
Acciddental or ingestion of toxic fungi
Their metabolites

Question 4

Mycotoxins Obersvations

Answer 4

• Not all moldy feeds/foods contain Mycotoxins
• Not all feeds/foods containing Mycotoxins are toxic
• Feed/food does not have to look moldy to be contaminated
• May not be uniformly distributed

Question 5

Toxic Mold Disease Endpoints

Answer 5

Allergy: Sensitization to mold or mold products
Mycosis: Direct infection by fungi
Irritation: Mechanical effects pf spores, mycelia debris
Mycotoxicosis: Response to toxins

Question 6

Mycotoxins

Transmission

Answer 6

Ingestion of contaminated plant material or feed

Question 7

Mycotoxins

Susceptibility

Answer 7

Species, age, and sex

Question 8

Mycotoxins

Clinical Findings

Answer 8

Acute or chronic; rapid death to tumor formation

Immunosuppression, organ degeneration, endo-crine disturbances, neoplasms, etc

Question 9

Mycotoxins

Diagnosis

Answer 9

History, clinical signs, and lesions

Detection of toxic levels of mycotoxin in the animal and/or feed

Question 10

Mycotoxins

Treatment

Answer 10

Remove source of toxin

Symptomatic

Question 11

Aflatoxicosis

Answer 11

Produced mostly by Aspergillus flavus and Aspergillus parasiticus

Question 12

Aflartoxicosis

Sources

Answer 12

Peanuts, corn, cottonseed, etc

Question 13

Aflatoxicosis

Specie Susceptibility

Answer 13

Poultry are more susceptible than mammals

Question 14

Aspergillus (AFLATOXINS)

Characterisitic

Answer 14

Dietary carcinogen
From Aspergillus flavus
Universal food contaminant
- Corn peanuts and wheat rice

Question 15

Types of Aflatoxins

Answer 15

B [blue fluorescence] group: B1 [most abundant] and B2
G [green fluorescence] group: G1 and G2
M: Found in milk

Question 16

Aflatoxicosis

Pathogenesis

Answer 16

-Primary target organ: Liver—hepatocellular necrosis, fatty degeneration, hepatoma, etc
Carcinogenesis—Activation of proto-oncogenes
-Immunosuppression
Depressed activity of phagocytes

Question 17

Diseases of Alfatoxicosis

Answer 17

Turkey X disease (birds)
Cancer in humans 
Pharmacological and clinical syndroms 
Anorexia and muscle weakness
Spasm and death
hemorrhage and necrosis of liver

Question 18

Aflatoxicosis

Clinical Findings

Answer 18

Acute—rapid death; hepatic necrosis, etc

Chronic—reduced weight gain, icterus, hepatic cirr-hosis, hepatoma or hepatocellular carcinoma, etc

Question 19

Alfatoxicosis

Diagnosis

Answer 19

Clinical signs and lesions
Detection of aflatoxins in feed, urine, milk, etc
Characteristic blue or green fluorescence of feed
Liver function tests

Question 20

Ergot alkaloids (Claviceps)

Answer 20

Bacteria: Claviceps purpurea 
Grows in wet and over wintered 
grains: rye, barle, wheat 
Sclerotia oor ergots 
      - Hard-packed mycelium
Ergotism
Gangrene and/or convulsions and gastrointestinal symptoms
Livestock: decreased weight gains, milk production, and reproductive efficiency

Question 21

Ergotism

Answer 21

Following ingestion of sclerotia [ergots] of Claviceps purpurea
Ergots replace the seed heads of wheat, rye-grass, barley, etc
Species affected
Mainly cattle, swine, sheep, and poultr

Question 22

Ergotism

Alkaloids

Answer 22

Ergotamine, ergometrine, ergocristine, etc

Question 23

Ergotism

Pathogenesis

Answer 23

Constriction of smooth muscles
Vasoconstriction—blood stasis and gangrene
Oxytocic action—abortion
CNS signs

Question 24

Ergotism

Clinical Findings

Answer 24

Gangrenous ergotism
Peripheral vasoconstriction
Convulsive ergotism
Abortion—cattle and swine
Agalactia
Prolactin inhibitor

Question 25

How Ergot Exposure Occurs

Answer 25

Claviceps purpure - spoil
Spores released when grain flowers
Land on stigma: germinate: hyphae extend into the ovary
Replaces the ovary - harden ergot body or sclerotium, recyle
- Seeds and sclerotida harvested together
- Screening techniques to remove the ergot based on size and weight
- Exposure occurs by ingesting grain/food