What are the characteristics of vomitoxin aka the DON?
-found in corn, wheat, and barley
-fungus grows best in the field while the DON increases during storage
-ideal conditions for the DON are cool, wet falls with delayed harvest
What is the pathophysiology of the DON?
-induces emesis by direct stimulation of chemoreceptor trigger zone in medulla oblongata
-inhibits protein synthesis
-may lead to poor production and/or immunosuppression
What are the clinical signs of the DON?
-emesis
-diarrhea
-feed refusal
-decreased feed intake
-impaired nutrient absorption
-poor production
How does the DON affect different species?
-swine are more susceptible
-ruminants are more resistant; require higher conc.
What are the clin path abnormalities seen with the DON?
-low Na
-low K
-dehydration
-metabolic alkalosis
What is the diagnosis, treatment, and prevention for the DON?
*diagnosis:
-detection in feed
*treatment:
-remove the DON
-provide supportive care
*prevention:
-do not feed the DON
-binders to reduce absorption
What are the characteristics of zeralonone?
-produced by same fungus as the DON
-found in corn and other grains
-produced in cooler temperatures compared to the DON
-estrogenic compound
What are the signs of hyperestrogenism in swine caused by zeralonone?
-swollen vulva and mammary glands
-prolapsed rectum
-overdeveloped repro. tracts
-nymphomania
-pseudopregnancy
-early embryonic death/infertility in older sows; smaller litters
-estrogenization of males; reduced testicular weight, ridden by other males
Why is zeralenone toxicity worse in swine compared to other species?
-delayed detoxification
-enterohepatic recirculation
What are the signs of zeralenone toxicity in dairy heifers?
-anestrous/delayed estrus
-swollen vulva
What are the characteristics of ralgro?
-synthetic zeralenol growth implant for beef steers
-use improves rate of gain by an additional 40 lbs
What is the treatment and prevention for zeralenone?
-remove offending feed
-use binders to prevent absorption
What are the characteristics of fumonisins?
-grow on corn
-highest concentrations in screenings and broken kernels
-severely affect horses and pigs
What is the pathophysiology of fumonisins?
-inhibit sphingolipid synthesis in neuron, myocardial and hepatocyte cell membranes
-cause liquefactive necrosis of myelinated neurons (chronic)
-induce myocardial necrosis and resulting heart failure and pulmonary edema
-cause direct hepatoxicity (acute, high conc.)
What are the characteristics of equine leukoencephalomalacia?
-moldy corn disease
-due to fumonisins
-liquefactive necrosis of white matter of cerebrum in horses
-occurs at small concentrations over chronic exposures
What are the clinical signs of equine leukoencephalomalacia?
-altered mentation; depression to excitability
-head pressing
-ataxia
-blindness
-seizures
-death; always fatal/leads to euthanasia
What are the characteristics of fumonisins in pigs?
-causes pulmonary edema and left-sided heart failure
-damage to left ventricle induces congestive pulmonary hypertension and edema
-clinical signs include sudden death, dyspnea, and cyanosis
What are the characteristics of acute fumonisin exposure?
-can cause hepatoxicity in any species
-clinical signs include icterus, ill thrift, and poor production
-clin. path. shows elevated cholesterol, AST, bilirubin, SDH, and GGT
What is the treatment for fumonisin toxicity?
there is no treatment
What are the characteristics of ochratoxin?
-potent nephrotoxic mycotoxin
-found in cereal grains, dried fruit, coffee, and wine
What is the pathophysiology of ochratoxin?
-damages proximal convoluted tubule cells
-lesions include hyaline casts, dilated tubules, and renal fibrosis
-ruminants break down ochratoxin and are less sensitive
What are the clinical signs of ochratoxicity?
-uremia
-depression
-anorexia
-reduced production
-diarrhea
-dehydration
-anuria/oliguria
-acute renal failure
What are the clin. path. findings in ochratoxicity?
-elevated BUN and creatinine
-excess protein in urine
-hyposthenuria
-casts in urine
What is the treatment for ochratoxicity?
-no specific treatment
-remove offending feed
-fluids and electrolyte correction for supportive care
