Mycotoxins Flashcards
Mycosis
Invasion in the organism by some part of the fungus
Mycotoxicosis
Mold growth is not directly involved in the host
Field Fungi
Fusarium, Pullaria, Alternaria
Grows under conditions prior to harvest
Die under usual storage conditions
Requirements for field fungi
Humidity over 80%
Moisture over 22%
Storage Fungi
Aspergillus, penicillin
Don’t invade intact grain prior to harvest
Humidity @ 70%, moisture 14-24%
Mycotoxins storage and transport
Dry samples: oven dry 176F-194F for 3 hrs
Reduce moisture to 12-23%
Long term: dry samples <12% and seal in moisture proof containers
Mycotoxin containers
Paper/ cloth bags
Avoid plastic bags
T/F: Mycotoxins have no specific treatment
TRUE
Mycotoxin prevention
Avoid contiaminated feed
Cleaning
Drying (13-25%)
Diluting with clean grain
Sources of alfatoxins
Aspergillus flavus, A. parasiticus
Corn, milo, cottonseed, peanuts
What enhances alfatoxin production
High humidity, grain moisture, drought stess
Fungal growth
Alfatoxin MOA
Inhibits and impairs protein synthesis
Interferes with transcription and fat metabolism
Hepatic Steatosis for alfatoxins
Due to lack of formation of lipid acceptor protein
What does hepatic steatosis lead to?
Decreased cellulose digestion
Reduced volatile fatty acid formation
Inhibition of proteolysis
Necrosis occurs
Alfatoxin B1
Most common and toxic
Forms covalent adducts with DNA,RNA and proteins
Alfatoxin M1
Carcinogenic potential
Milk, urine, tissues
Metabolite of B1
Alfatoxins species susceptibility
More severe in young
Poultry and monogastrics susceptible
Swine, dairy cattle, nutritionally deficient animals
Signs of alflatoxicosis (acute toxicosis)
Depression, anorexia, WL, malabsorption, bloody stools, ↓ milk production, subnormal temp.
Chronic alfatoxicosis in poultry
Pale bird syndrome, ↓ feed efficiency, stetarrhea, ↓ growth rate, ↑ capillary, bruising
Chronic alfatoxicosis in swine
Ascites, mild anemia, icterus, slow growth, anorexia, unthriftiness
Chronic alfatoxicosis in cattle
Reduced production and reduced rumen motility
Alfatoxicosis pathology
Liver is the major target organ
Degeneration and necrosis
Fatty change, bile duct proliferation
Testing and analysis of alfatoxins
Black light test
Thin layer chromatography
Gas-liquid chromo.
Mass Spectrometry
Alfatoxins black light test on corn
UV light gives a bright yellow fluorescence due to kojic acid marker
Fluorescence: broken or damaged grains
Alfatoxins tissue analysis
Milk and urine: M1 detectable 7-15d
Liver and kidney: excreted 72-96h and residue dissipates after 14d
Alfatoxin treatment
Hydrated sodium calcium alumino-silicate
Vit. E and Selenium
Alfatoxin prevention
Anhydrous ammonia (treat grain 10-14d)
Mold inhibitors
FDA guidelines for alfatoxins
Actionable level 0.5 ppb in milk (1%)
Zearalenone sources
Fusarium roseum and F. monilforme
Corn, wheat, barely, milo
Zearalenone fungal growth
Pink ear rot, scab
Zearalenone MOA
Alters DNA and RNA synthesis
Weak estrogenic effects
Inhibits FSH and ovarian maturation
Zearalenone susceptibility
Swine (prepubertal females/ gilts)
Zearalenone in swine
Hyperestrogenism
Swelling, edematous vulva, enlarged mammary gland, tenesmus, rectal/ vaginal prolapse
Zearalenone in mature cows
Nymphomania syndrome
Prevents follicular development
Pseudopregnancy/ anestrus syndrome