Selenium & Molybdenum Flashcards
early work on selenium was concerned with its toxic effect on what kind of animals?
grazing
In 1935 at the S. Dakota Expt. Station it was first demonstrated that selenium was the toxic factor in the forage which causes what disease
“alkali disease” or “blind staggers”
In certain areas which have Se deficient soils (where most grains and forages are low in Se) a disease of calves and lambs known as _____ ______ ______ occurs frequently
White muscle disease
addition of how much Se in the ration of the dam has been successful in preventing white muscle disease
0.1 ppm
4 consequences of Se deficiency
1) INcrease mortality of newborn lambs and calves
2) white muscle disease in lambs and calves
3) exudate
4) liver necrosis in rats - also prevented by vit. E
____ is a component of the enzme glutathione peroxidase that eliminates the peroxides which oxidize other components which cause damage
Se
Se protects the body from peroxides in
cytoplasm
Se is readily absorbed in the _________ ________ and transported in the plasma to all parts of the body
anterior duodenum
Se is primarily stored in the _____ & _______
liver and kidneys
Se is excreted via
urine>feces>expired air
animals containing high concentrations of Se also lose some in ___ and _____
hair and hoofs
Consequences of selenium toxicity
hair loss: mane & tail in horses; tail in cattle; general hair loss in swine.
hoofs slough off, lameness occurs, feed consumption decreases and eventual death from starvation occurs.
what levels must be reached for acute Se toxicity
500 ppm
any soil containing more than ___ Se are potentially dangerous
0.5 ppm
Where is Molybdenum distributed
throughout the body, with the concentration varying among the different tissues
like Se, molybdenum is primarily known for its toxic effects to
grazing animals of certain areas of the world
the essentiality of Mo is largely ascribed to its cofactor role for ____ _____ and _____ _____
xanthine oxidase and aldehyde oxidase
a metalloflavoprotein enzyme that is essential in purine metabolism
xanthine oxidase
Mo is a possible nutritional role in the growth of lambs via
potential stimulatory effects on rumen microbes
Mo is necessary in the nitrate reductase system to convert
nitrates to nitrites in plants
if the reduction of nitrates to nitrites does not occur we can get ___ ___ from the plants when fed to animals
nitrate toxicity
Mo is readily absorbed from the
digestive tract
excessive dietary sulfate reduces
Mo absorbability
Mo is primarily excreted through the
Kidneys
disease characterized by severe scouring (diarrhea) and loss of condition in cattle confined to these pastures
teartness
Animals affected by Molybdenum toxicity
cattle > sheep , horses not effected
Tolerance of animal species to Mo: ruminants chicks rabbits horses
toxic level of Mo, ppm R: 10 C: 300 Rab: 500 H: >1000
3 things tolerance of Molybdenum is affected by
- chemical form of molybdenum
- copper status and copper intake of the animal
- level ofintake of other metals, including Zn and Pb
Se deficiency areas are predominately
pacific NW, the NE and along the SE seaboard
*** Se toxicity is more likely in what state? Florida or South Dakota?
South Dakota
