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79 Cards in this Set
- Front
- Back
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Most mycotoxins are a result of what production?
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filed production
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What produced aflatoxin?
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Aspergillus flavus
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What crop is Aflatoxin associated wtih?
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corn
-also cotton seed and peanuts |
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What is the main factor that brings about production of aflatoxin?
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drought years
insect damage |
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What metabolite of A. flavus can be seen with a black light on corn?
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kojic acid
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Of the 4 Alflatoxins in feeds, which is most toxic and prevalent?
What is it metabolized to in the cow and where is it then excreted? |
B1
-metabolized in body to Afla M1 which comes out in milk -monitored by FDA because it is carcinogenic |
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Who is the most susceptible animal to aflatoxin and who is the most resistant?
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susceptible - young and breeding animals (poultry, horses, dogs) >
finishing animals (cattle, swine, sheep) most resistant |
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Where are REAL LIFE toxicoses most likely in -with aflatoxin which animals>
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poultry and young swine
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What level does the FDA have to control aflatoxins shipped interstate?
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action levels - can step in to control
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How do aflatoxins work?
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bind intracellular macromolecules esp in the liver to decrease RNA synthesis.
-immunosuppressive (CMI) -hepatotoxic and carcinogenic |
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What are the systems affected by aflatoxins?
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Hepatic, General ADR
-jaundic, rough hair coat, eat and produce less |
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What can you add to the diet to blend contaminated feed below the threshold?
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anti-caking clays to bind aflatoxin in intestinal contents and prevent absorption
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What produces vomitoxin, the most common trichothecene?
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Fusarium graminearum (AKA F. roseum)
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What is another common name for vomitoxin??
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feed refusal factor
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What season is vomitoxin produced in?
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wet, growing seasons
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What plant is vomitoxin produced on?
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corn and most small grains
-grain may have pink or rose color -scabby grain or pink ear rot of corn |
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What animals is vomitoxin most toxic for?
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swine and dairy cattle
-poultry, sheep and beef cattle are farily RESISTANT because rumen microbes degrade epoixde |
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What is the main system affected by vomitoxin?
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GI - feed refusal is immediate; diarrhea 1-2 days later
-high morbidity, low mortality |
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What is the only solution for the treatment of trichothecene feed?
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dilution - remove or bled feed below the threshold
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What produces zearalenone?
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Fusarium toxin (same that produces vomitoxin)
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What plant is zearalenone produced on?
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corn, small grains
-corn stored on the cob in open air cribs is especially likely to be contaminated (with >14%) |
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What is the most susceptible species to zearalone toxicity?
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swine
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What is the MoA of zearalenone?
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acts as an estrogen
zearalenone --> zearalenol (in body) --> zearalanol (found in estrogenic plants) |
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What is the main system hit by zearalenone?
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reproductive (4-7 days)
-enlarged uterus, hypoplastic ovaries or increased CL formation |
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Will anti-caking clays work with zearalenone?
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no
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What produces slaframine?
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Rhizoctonia leguminicola
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What plant is affected by slaframine?
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hay
-grows on legumes (CLOVER, also alfalfa, lespedeza and black medic) -second cutting red clover most common in this area |
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What can be see on the stems or leaves of hay that has slaframine?
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black patches
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What animal is slaframine a problem?
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horse
-also goats -possible in cattle and sheep |
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What is the MoA of slaframine?
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a parasympathomimetic alkaloid that is metabolized in the liver within an hour to ketoimine, the active principle
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What is the active priniciple in slaframine?
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ketoimine
-structure similar to Ach that works on recpetors esp associated with exocrine salivary glands -charge prevents crossing the BBB |
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What is the main system affected by slaframine?
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GI
-salivation and lacrimation -loose a lot of electrolytes - dehydration |
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What could you use on a horse with slaframine toxicity?
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antihistamines
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What produces ELEM (Fumonisin)?
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Fusarium verticilliodes (F. moniliforme)
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What plant is fumoniisin on?
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corn (cracked kernels)
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What conditions allow fumonisin to grow?
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dry season followed by wet harvest
-can be contaminated with aflatoxin and vomitoxin |
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When do most cases of fumonisin occur?
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coldest months
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Fumonisin causes most problems in what animals?
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ALL equidae
-swine next susceptible |
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What do fumonisins inhibit - ie what is their MoA?
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-inhibit sphingolipid biosynthesis
-important for myelin formation and integrity in brain (horse) -important in heart/endothelial cells (swine pulmonary edema problem) |
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What are the main signs of fumonisin toxicity in the horse?
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CNS most common
-1-4 weeks onset -blindness, bizarre maniacal behavior (horse goes bonkers) -liquefaction necrosis of white matter of the brain -HEPATIC - rare -yawning |
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Is there high mortality in horses with fumonisin toxicity?
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yes
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What are some sources of tremorgens?
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-aspergillus and penicillium
-neotyphodium lolii endophyte in perennial ryegrass -bermuda grass |
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What produces penitrem A and where can it be found?
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penicillium molds
-moldy milk products and moldy english and black walnut hulls |
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What produces roquefortine and where is it found?
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penicillium molds growing on decaying organic matter, garbage, compost piles, road kill, deer carcass, poultry litter, bone meal
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Name 2 tremorgens that are commonly found together.
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penitrem A and roquefortine
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What animals are most affected by penitrem A and roequefortine?
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dogs - on top 5 of canine toxicants
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What is the main clinical sign associated with tremorgens?
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CNS
-high stepping -clonic-tonic convulsions -hyperesthesia -paralysis/prostration (low dose) |
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What is the source of ionophores and what do they do in teh body?
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Streptomyces fungi and facilitate transfer of ions across membranes
-used as coccidiostats and to increase feed efficiency |
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Give some examples of ionophores?
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monensin - most common
-lasalocid (more common with dogs) -salinomycin |
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In order of most susceptible to least, what animals are susceptible to ionophore toxicity?
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horse>sheep>swine>cattle>chicken
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What potentiates monensin toxicity?
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concurrent exposure to macrolide and some other antibiotics that inhibit cytP450
-monensin most common cause |
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What is the therapeutic action of ionophores?
the toxic action? |
therapeutic - favors growth of bacteria that make more propionic acid in ruminants - most efficient volatile fatty acid energy source
-toxic - related to influx of ions across mitochondrial membranes of HEART and SKELETAL MUSCLE - leading to calcium accumulation intracellularly and cell death and necrosis |
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What are the target organs of ionophore toxicity?
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heart and skeletal muscle - tissue that needs lots of energy and have lots of mitochondria
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Name some of the effects of ionophores?
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-free radiacal formation
-lipid peroxidation -catecholamine release -intracellular Ca accumulation mitochondrial accumulation of Ca with swelling and opening of MPTP -decreased ATP formation -cell necrosis |
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What are the main systems affected by ionophore toxicosis in horses?
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cardiac, skeletal muscle, GI
-heart>skelettal muscle -sweating, weakness in hind limbs -tachycardia |
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What are the main systems affected by ionophore toxicosis in ruminants?
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cardiac, skeletal muscle, GI
heart = skeletal msucle -reluctance to walk -pale heart, and skeletal muscles -hydrothorax -myoglobinuria in sheep |
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What are the main systems affected by ionophore toxicosis in dogs and cats?
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-cardiac and skeletal muscle
-dog has rear leg skeletal muscle problems -cat has more heart problems -death from respiratory paralysis |
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What is the treatment for ionophore toxicity?
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-activated charcoal with saline cathartic
-fluids and steroids -vitamine E/selenium stall rest for 6 weeks |
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What produces cantharidin?
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blister beetles - in hemolymph glands
(Epicauta) -fat soluble and quickly absorbed from GI tract |
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What plants is cantharidin associated with?
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3rd cutting alfalfa hay from SW US
-also possible with other legumes -crimped hay more likely to kill beetles -beetles congregate in small groups on edge of pasture |
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What animals have the most toxicity with cantharidin?
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horses
-allso occurs in cattle and sheep |
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What is the MoA of cantharidin?
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cantharidin is strong mucosal irritant - injures GI and oral mucosa going in and renal/bladder structures coming out
-produces hypocalcemia -heart injury |
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What are the main systems affected by cantharidin toxicity?
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GI, Renal , Cardiac
-pollakiuria -FEVER! -synchronous diaphragmatic flutter (hiccups) |
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What is the onset of cantharidin?
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less than 2 hours
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What 2 def are seen with cantharidin?
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hypo - Mg and Ca
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Where is gossypol from?
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-polyphenolic pigment that is in glands of cotton seeds
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What extraction method increases gossypol conc and what has more cotton seed meal or whole cotton seed?
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-solvent extraction of cotton seed ruptures more glands
more in cotton seed meal |
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Which ruminants are more susceptible to gossy pol?
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immature ruminants and swine
-poultry as intermediate (mature ruminants have high amounts of amino acids in rumen - resistant to gossypol) |
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What is the case mortality rate of gossypol toxicity?
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>50%
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What is the MoA of gossypol?
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inhibition of protein synthesis and inhibition of a variety of enzymes in body
-can disrupt repro hormone balance (affects sperm) |
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Is gossypol a cumulative toxicant?
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yes
(onset is 1-3 months) |
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What are the main systems affected by gossypol?
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cardiac, hepatic, reproduction
-tachypnea (thumps) |
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What is a method of gossypol tox prevention?
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-increase protein in diet to inactivate free gossypol in gut
-pelleting -increase ferrous sulfate content of diet so iron: gossypol ratio is 1:1 -watch cotton seed meal content |
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List the common sources of salt toxicosis with various animals.
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cattle - eating too much mineral with reintroduction after several weeks of going withour
poultry - misformulation in diet swine - water deprivation assocated with freezing or failure dog - ice melt or salt as an emetic , play dough |
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What are the main systems affect by Na toxicosis in cattle ?
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CNS, GI Syndrome
-blindness -onset time is quicker - less than 12 hours |
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What are the main systems affect by Na toxicosis in swine?
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CNS syndrome
-blind, star gazing, jaw champing, eosinophil cuffing in brain -onset time is >3 days |
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What are the main systems affect by Na toxicosis in poultry?
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cardiovascular system
-onset time is 1-2 days |
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What are the main systems affect by Na toxicosis in dogs?
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CNS, GI Syndrome
-onset time is < 4 hours |
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What is the treatment for swine and cattle with Na tox?
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access to small amounts of water at one hour intervals until rehydrated
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