Nutritional Toxicology Flashcards
What is toxicology?
the science dealing with the identification and study of poisons (toxicants) as well as the prevention and treatment of poisonings and toxicity diseases
What is nutritional toxicology?
a subfield of toxicology that studies poisons and toxicants delivered to an animal orally
What is the LD50 in small animal medicine?
the amount of toxin that kills 50% of animals
What defines a toxin?
All substances are poisonous, but the dose differentiates a poison and remedy
What is the difference between graded dose response and quantal dose response?
graded dose-response is an individual response characterized by dose-related changes in severity of the toxic response
quantal dose response is a population response characterized by dose changes in the number of individuals of a population responding
What are the phases of toxicity?
exposure, toxicokinetic, and toxicodynamic
The ______ determines the rate/extent of absorbtion
transporter
______ dictate transportation
chemical properties
Primary elimination is through the _____ and _______
urine and bile
Secondary elimination happens through _________ ,________, __________, __________, and _________
lungs, sweat glands, salivary glands, mammary glands, and metabolism
Mycotoxins are produced by _____
fungi
Mycotoxins are associated with _____
food/feeds and in the field (during growth of a plant)
What are the types of toxic modes of action?
reversible interactions, irreversible (covalent) interactions, and physical sequestration
Swainsonine is also known as _____
Locoweed
Tall Fescue and Endophyte have a _______ relationship
mutualistic, symbiotic
Endophyte helps Fescue by ______
protecting against biotic and abiotic stress, alkaloid production, improved persistence and resistance to drought, deeper root development, increased tillering, improved nutrient uptake, nitrogen and increased water use efficiency
Fescue helps Endophyte by _____
protecting, nutrition, and transmission
Tall fescue + endophyte produced ergot alkaloids =
improved plant performance and ANIMAL TOXICITY
What are effects of fescue toxicosis?
reduced reproductive performance (reduced conception, prolonged gestation), agalactia/reduced milk production, reduced growth performance (summer slump), heat stress complications (summer slump), and gangrene of extremities (loss of tail, ear tips, and feed; fescue foot)
What is the effect of Swainsonine?
Swainsonine Induced Spongiform Encephalopathy
What is Swainsonine mode of action?
Inhibition of mannosidase enzymes, lysosomal form (lysosomal storage disease), Golgi form (high mannose type glycoproteins)
What species are primarily affected by nitrates?
cattle, goats, horses
There is slow plant growth under:
heavy nitrogen fertilization and “Stress” of drought
What is a nitrate accumulator?
redroot pigweed, cloudy weather and low temperatures
Nitrate stays in dried forages but is ______ in ensiled forages (silages, haylage)
reduced
Nitrates turn into ______ in ruminants
nitries
Nitrites lead to ______ formation, which leads to anoxia and death since the blood cannot carry oxygen
methemoglobin
Who is most susceptible to nitrate poisoning?
naive, young cattle
hungry cattle
cattle not adapted to high levels
NItrate poisoning can lead to ______ if it reaches the fetus
abortion
How do you prevent nitrate poisoning?
ensiling (reduces 40-60%), dilute with low nitrate feed, increase tolerance, apply nitrogen fertilizer annually (to soil and plant level needs), and sample and test forages for nitrate levels
What species are susceptible to cyanide poisoning?
horses, cattle, sheep, swine, and goats
Poisoning usually follows plant _____
damage
What plants should not be grazed upon for at least 48 hours to 14 days?
frosted plants
What are the effects of cyanide poisoning?
prevention of oxygen release, cherry red blood, dyspnea, weakness, paddling, seizure, death, severe respiratory difficulty, and sudden death
What species are affected by Showy Crotalaria?
chickens, horses, cattle, swine
- sheep, goats, mules, and dogs (of a lesser degree)
What are the symptoms of Showy crotalaria ingestion?
causes severe liver disease
poultry: diarrhea, pale comb, ruffled feathers, depression
horses: chronic unthriftiness, incoordination, head press, jaundice
cattle: bloody diarrhea, icterus, weakness
swine: gastric hemorrhage, death, anemia, ascites, alopecia
What is the treatment for Showy crotalaria?
no specific treatment
What species are affected by Horsenettle (Nightshade)?
all livestock, poultry, humans
What are the symptoms of Horsenettle (Nightshade)?
acute - GI tract lesions, mouth irritation
chronics - unthriftiness, constipation, jaundice
equine - colic
What is the treatment for Horsenettle (Nightshade)?
supportive care, laxatives, absorbents
What is the toxic principle of Showy crotalaria?
monocrotaline (alkaloid)
What is the toxic principle of Horsenettle (Nightshade)?
solanine (alkaloid)
What species are affected by oleander?
all livestock and humans
What is the toxic principle of oleander?
glycosides (oleandroside and nerioside)
What are the symptoms of Oleander ingestion?
severe gastroenteritis, diarrhea, abdominal pain, sweating, weakness, irregular heartbeat
What is the treatment for Oleander digestion?
symptomatic (largely unsuccessful)
A single leaf from what plant can cause death?
Oleander
