Exam 4 - Feed and Water Contaminants Flashcards
What are the sources of food contaminants? How do they get there?
Supplementation
Why is melamine relatively non-toxic when given as a single agent but shows toxicity when combined with cyanuric acid?
Relatively non-toxic when consumed independently-may be due to dog and cat microbiota or concentration
When combined with cyanuric acid → crystalline lattice under acidic conditions → renal toxicosis & failure
What major subclass of ionophore is used as a food additive?
Carboxylic ionophores (e.g. monensin)
What is the proposed mechanism of action associated with ionophore toxicosis and what are the primary clinical signs?
transport of ions across biological membranes
loss of ATP production in mitochondria
neuromuscular in pigs, dogs, cats
cardiac in cattle
What treatment options are available for ionophore toxicosis?
GI decontamination
vitamin E or Selenium
supportive care - good nutritional husbandry and support
What are the primary organ systems and processes affected by gossypol?
cardiac - primarily degeneration & necrosis of myocardium
respiratory
reproductive - anti-fertility
liver toxicity
What animals are more or less susceptible to gossypol poisoning and why?
Ruminants more resistant than monogastrics due to gossypol ability to bind to proteins in rumen
What form of sulfur is responsible for the toxicosis and where does it come from?
Sulfide (S2-/H2S) overproduction by rumen microflora in ruminants
What is the primary toxicosis associated with sulfur exposure in ruminants?
Polioencephalomalacia (PEM)
Why is feed ammoniated and what type of feed poses the biggest danger from ammoniation?
increase digestibility
increase intake
increase crude protein content
allow storage of higher moisture roughage by inhibiting mold development
toxicity occurs more frequently with high quality forages
What product of ammoniation is thought to be responsible for toxicosis and when is it formed?
Pyridines and imidazoles formed by maillard reaction are found in the hay
Why are nursing calves and lambs susceptible to toxicosis associated with ammoniated feed?
can be transferred in the milk to neonates
How is NPN processed in the rumen and what is the toxic component that is generated?
NPN increases production and accumulation of ammonia with alkaline pH
ammonia
What role does pH play in this process?
Alkalinity drives ammonia into the liver & excess ammonia escapes urea cycle → systemic circulation
What role does the liver play in NPN toxicosis?
Liver converts ammonia to urea but if there is too much ammonia the liver cannot convert it all and excess ammonia will enter systemic blood
