Molds, Mycotoxins, and Ergots Flashcards
What is a mycotoxin?
A secondary metabolite/chemical of a fungus producing toxins in other orgs. that are always immunosuppressive
What is the number one cause of diarrhea in animals? What about the second most common cause?
Diet; parasites
Two classifications of metabolites of fungi are:
- Field Fungi
2. Storage Fungi
Field fungi–>
growing in plant while out in a field before processing occurs. Grow BEFORE HARVEST
Storage fungi–>
Do not invade grain before harvest but rather in conditions that damage the seed coat thus predisposing to fungal growth
Mycotoxin is often causes what conditions?
Often cause vague, subacute or chronic conditions
ALL MYCOTOXINS ARE ______
IMMUNOSUPPRESSIVE
What are two ways in which we can test for mycotoxins?
Testing feeding suspected rations, ID known mycotoxins in diet or in bodily tissues
What conc. of mycotoxins are considered safe?
NONE!!! ALL are responsible for some aspect of immunosuppression!!!!**
What are the toxigenic molds and mycotoxins thought to be most prevalent and toxic to dairy cattle??? (three of them)
Fusarium, Aspergillus, Penicillium
Fusarium subspecies we must know:
Deoxynivalenol, Zearalenone, T2 toxins, Fumonisin
What is the one Aspergillus toxin subsp. we must know?
Aflatoxin
What is the one Penicillium toxins subsp. we must know?
PR toxin
Aflatoxin is a potential carcinogen in humans, what is the primary targeted organ? What does it lead to?
Liver; leads to loss of proteins, improper antibody formation, decreased clotting factors
Alfaltoxin- what animals are more susceptible? What animals seem to be the most resistant to the acute forms?
Younger animals; adult ruminants
Diagnosis in lab for aflatoxin:
Increased liver enzymes, hyperbilirubinemia, decreased albumin, decreased prothrombin, M1 marker in milk/urine, black light positive
Aflatoxin lesions of acute infection are found as….
hepatic necrosis, gall bladder edema, ascites
Aflatoxin tx—>
Hydrated sodium calcium aluminosilicate (HSCAS)- toxin binder and supplements with Vit E and Selenium
Prevention of Aflatoxin–>
Mold inhibitors, tx with grain and anhydrous NH4 (ammonia)
Public Heath concerns of Aflatoxin toxicity:
Aflatoxins are carcinogens, milk is monitored closely for M1 metabolites– legal limit is 0.5ppb. Milk from cows fed more than 20ppb (legal limit of grain for cows that are lactating) may contain milk residues that are over the legal limit
What is the ratio used to find conc in feed from how much is in the milk?
40:1 ratio is used between ppb residue in milk and how much is in the feed
Zearalenone causes…
Fungal infections “scabs”
What enviro. does Zearalenone prefer to grow?
High moisture and alternating high and low temps. Cooler morning followed by hotter afternoons
Zearalenone is absorbed in the ___ ____ and may be secreted in _____ without any regulatory restrictions
GI tract; milk
Mode of action of Zearalenone:
Binds to receptors of estradiol and functions as a weak estrogen, inhibiting secretion and release of GnRH which stimulates ovulation and is released from the hypothalamus.
What species are most affected by Zearalenone, what are the least susceptible species?
Most: swine
Least: Cattle
Zearalenone lab diagnosis:
Increased plasma progesterone
Zearalenone lesions in the body:
Ovarian atrophy and follicular atresia, follicular cysts, uterine edema and cystic appearance, proliferation of mammary tissues
Zearalenone tx and prevention includes…
TX–> removing source, bovine repro effects can last 2+ months, activated charcoal may help + GnRH or HCG/PGF2alpha
Prevention–> Betonite clay binder to contaminated diets
Trichothecenes (aka T2, DON, Vomitoxin) sources
Corn, milo, cereal, wheat
Conditions for Trichothecenes (aka T2, DON, Vomitoxin) to grow the most:
Alternating warm and cool and late harvested or overwintered grains
Trichothecenes (aka T2, DON, Vomitoxin) characteristics include what type of environment?
Stable environment, they are resistant to heat and pressure cooking/processing :((