Mycotoxins Flashcards
Mycotoxins Characteristis
Non-antigenic, heat-stable metabolites of filamentous fungi [plant pathogens]
Produced by fungi growing on crops or in stored feed
Mycotoxins
Predisposing factors
Availability of usable substrate
Ambient temperature [20oC to 30oC]
Moisture
Damage by insects and harvesting machines
Mycotoxicoses
Diseases associated with fungal toxin
Acciddental or ingestion of toxic fungi
Their metabolites
Mycotoxins Obersvations
- 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
Toxic Mold Disease Endpoints
Allergy: Sensitization to mold or mold products
Mycosis: Direct infection by fungi
Irritation: Mechanical effects pf spores, mycelia debris
Mycotoxicosis: Response to toxins
Mycotoxins
Transmission
Ingestion of contaminated plant material or feed
Mycotoxins
Susceptibility
Species, age, and sex
Mycotoxins
Clinical Findings
Acute or chronic; rapid death to tumor formation
Immunosuppression, organ degeneration, endo-crine disturbances, neoplasms, etc
Mycotoxins
Diagnosis
History, clinical signs, and lesions
Detection of toxic levels of mycotoxin in the animal and/or feed
Mycotoxins
Treatment
Remove source of toxin
Symptomatic
Aflatoxicosis
Produced mostly by Aspergillus flavus and Aspergillus parasiticus
Aflartoxicosis
Sources
Peanuts, corn, cottonseed, etc
Aflatoxicosis
Specie Susceptibility
Poultry are more susceptible than mammals
Aspergillus (AFLATOXINS)
Characterisitic
Dietary carcinogen
From Aspergillus flavus
Universal food contaminant
- Corn peanuts and wheat rice
Types of Aflatoxins
B [blue fluorescence] group: B1 [most abundant] and B2
G [green fluorescence] group: G1 and G2
M: Found in milk
Aflatoxicosis
Pathogenesis
-Primary target organ: Liver—hepatocellular necrosis, fatty degeneration, hepatoma, etc
Carcinogenesis—Activation of proto-oncogenes
-Immunosuppression
Depressed activity of phagocytes
Diseases of Alfatoxicosis
Turkey X disease (birds) Cancer in humans Pharmacological and clinical syndroms Anorexia and muscle weakness Spasm and death hemorrhage and necrosis of liver
Aflatoxicosis
Clinical Findings
Acute—rapid death; hepatic necrosis, etc
Chronic—reduced weight gain, icterus, hepatic cirr-hosis, hepatoma or hepatocellular carcinoma, etc
Alfatoxicosis
Diagnosis
Clinical signs and lesions
Detection of aflatoxins in feed, urine, milk, etc
Characteristic blue or green fluorescence of feed
Liver function tests
Ergot alkaloids (Claviceps)
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 efficiencyErgotism
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
Ergotism
Alkaloids
Ergotamine, ergometrine, ergocristine, etc
Ergotism
Pathogenesis
Constriction of smooth muscles
Vasoconstriction—blood stasis and gangrene
Oxytocic action—abortion
CNS signs
Ergotism
Clinical Findings
Gangrenous ergotism Peripheral vasoconstriction Convulsive ergotism Abortion—cattle and swine Agalactia Prolactin inhibitor
