Micronutrients Flashcards
What are vitamins?
Vitamins are organic substances, present in small amounts in natural
foodstuffs, which are essential to normal metabolism and lack of which cause deficiency diseases
What do vitamins differ in?
Solubility
What are the fat soluble vitamins?
Fat soluble vitamins: A, D, E and K (KADE)
What are the water soluble vitamins?
B vitamins (B1, B2, B3, B5, B6, B9, B12, biotin, choline), vitamin C
What do vitamins do in regards to enzyme activity? what other effects can they have within the body?
Many vitamins act as cofactors for enzyme activity, and some have effects such as being methyl donors, as well as gene translation and activation
What happens when minerals interact with each other?
Minerals may interact with each other, therefore the requirement for one mineral
may be impacted by the amounts of other minerals
- For example- divalent cation minerals may compete and decrease absorption of each
other (Zn2+; Ca2+; Mg2+ )
TRUE OR FALSE: Some minerals in excess can lead to adverse effects?
TRUE
What essential nutrients are required for normal red cell production?
- Iron
- Folate (Vitamin B9 )
- Pyridoxin (Vitamin B6)
- Cobalamin (B12)
What is Iron used for ?
Essential for hemoglobin
What is folate required for?
is required for nucleotide synthesis. Important for rapidly dividing
cells
What B vitamin is Folate?
B9
What B vitamin is Pyridoxin?
B6
What is Pyridoxin required for?
important for protein synthesis
What B vitamin is cobalamin?
B12
What is B12 important for?
important for nucleotide synthesis, contains cobalt
Anemia caused by B12 deficiency is called?
Macrocytic Anemia
Anemia caused by Iron deficiency is called?
Microcytic Anemia
Where can ruminants/ hindgut fermenters receive their cobalamin?
They can rely on their gastrointestinal microbiota for cobalamin if there is enough cobalt in diet.
What is an iron deficiency?
Iron deficiency can occur as a result of either low intake or increased losses
What can cause iron losses in the body?
Chronic blood loss
- Internal parasites
- External parasites
- Tumors, Ulcers.
What can cause Heinz Body anemia?
Garlic/ Onion Ingestion
What is Haem Iron?
Haem iron is from haemoglobin in meat and fish and is in the reduced ferrous form.
What occurs with Haem iron in the stomach?
Haem containing iron in Fe2+ form is hydrolyzed from protein ‘globin’ component
What occurs to Fe2+ as it enters the small intestines?
Fe2+ remains soluble as it is bound to proteins and absorbed through enterocytes.
What is non haem iron?
Non Haem Iron is from plants and is in the oxidized Fe3+ (ferric) form.
What occurs in the stomach with non haem iron?
Some of the Fe3+ is reduced to Fe2+ in acid conditions of the stomach
What occurs to non haem iron / Fe3+ in the small intestines?
Some Fe3+ forms insoluble complexes at high pH of small intestine, lowering absorption rates and increasing excretion.
Which is more absorbable. Haem or Non haem Iron?
Haem Iron is more absorbable ( Already in Ferrous form)
Where is Haem Iron from?
Meats and fish
What percentage of haem iron is absorbed?
Depending on the individuals iron stores 15-35% of haem iron is absorbed.
What is the absorption rate of non haem iron?
2-20%
What can increase absorption of non haem iron?
Vitamin C
Why would vitamin C increase absorption of haem iron?
acidic pH will cause the reduction of ferric (Fe3+) to ferrous (Fe2+) iron, which sees to be a requirement for the uptake of iron into mucosal cells.
Which has more bioavailability, Haem or non haem iron?
Haem iron
What is vitamin A important for?
Epithelial health
What form is Vitamin A found in?
Vitamin A is found in the form of retinol (retinoic
acid) and beta carotene (provitamin A)
Herbivores are very efficient at doing what (in regards to vitamin A)?
Herbivores are efficient in the transformation of beta
carotene to retinol
TRUE or FALSE: All species can cleave beta carotene?
Not all species can cleave beta carotene
Where is retinol stored?
Retinol is stored in the liver and kidneys
What are the important functions of vitamin A?
- Maintain normal epithelial function
- Maintain immune function
- Vision
Do carnivores easily convert Vitamin A? Why?
Carnivores have more trouble converting Vitamin A since they are eating herbivores who have already transferred it into Retinol
What clinical signs can you see in patients with vitamin A deficiencies?
can cause brittle nails/ skin, higher incidence of ulcers.
What can destroy carotenoids?
Storage heat or direct sunlight.
Where is there an issue with storage and carotenoids being destroyed?
In developing countries if hay is stored improperly.
What are clinical signs of Carotenoid deficiency?
- night blindness (nyctalopia) - visual
pigment deficiency - Xerophthalmia (dry eyes; corneal
opacity)
What is zinc?
- Zinc is an essential mineral required
in the diet in micro amounts - Zinc is a cofactor for the enzyme
Super Oxide Dismutase (SOD) that is
important as it catalyzes the
dismutation of superoxide radicals
(O2−) to molecular oxygen (O2) and
hydrogen peroxide (H2O2), providing
cellular defense against reactive
oxygen species
What can cause zinc deficiency in livestock and pets?
Zinc depleted soils
What will likely cause the issues seen in this image?
Zinc hyperkeratosis, crusts, fissures and bleeding.
Zinc deficiency
Where can zinc be found in high quantities?
Zinc is high in plants grown on zinc replete soil (especially beans, legumes)
Zinc is high in internal viscera (kidneys, liver), and in red meat
What can can cause dietary inhibition of zinc absorption?
- Gi Disease
- excess calcium, copper, or
phytates)
What is primary reason for zinc deficiency?
Not enough zinc in diet.
Where is Phytic acid high?
Phytic acid is high in beans that are often used as pig feed
What can be added to pig diets to enhance zinc availability?
Phytase can be added to pig diets to enhance zinc (and phosphorus) availability
What dog breeds have more of a predisposition to zinc deficiency?
Northern breeds ( Husky/ Malamute)
What is a primary reason dogs have zinc deficiency?
Diets that are unbalanced or poor quality
What clinical signs would you see in a dog with zinc deficiency? Is this permenant?
Hyperkeratosis around the eyes, elbows and joints
Usually resolves when they receive the adequate amount of zinc (Ie diet change or supplementation)
What is oxidation?
Oxidation is a process by which a substance loses one or more electrons; the substance that gains the electron(s) is called an oxidant
What does normal cellular respiration generate?
Normal cellular respiration generates several oxidant compounds- reactive oxygen species (ROS)
What ROS are produced by normal cellular respiration?
Superoxide radical
Hydrogen peroxide
Hydroxyl radical (OH-)
What are most succeptible to damage by ROS?
Polyunsaturated fatty acids
What are poly unsaturated fatty acids? Where are they found?
Polyunsaturated fatty acids (PUFA) are a component in the phospholipids that
compose cell and organelle membranes
What do PUFA’s posess in terms of bonds?
PUFA possess unsaturated carbon or double bonds (C=C-)
What process is occuring when these PUFA are exposed to ROS?
Lipid peroxidation
Peroxidized PUFA’s can cause what?
Further oxidative damage
What is the chain of events of cellular damage due to lipid peroxides?
- Phospholipid bilayers are excessively permeable which will disrupt normal cellular and organelle function. Excessive damage can lead to cellular death.
What is vitamin E? What allows it to integrate into the cellular membrane?
Vitamin E is a fat-soluble vitamin but also has water solubility (amphipathic) which allows integration into cellular membranes
What is a provess involved with stabilization of free radicals?
Free radicals may reach the phospholipid bilayer, alpha tocopherol donates its own hydrogen atom and electron to the radical, stabilizing it
What is the results of the stabilization of free radicals?
This results in a non-reactive, oxidized alpha tocopherol form that can be reduced by vitamin C
What will reactivate vitamin C?
Vitamin C, in turn, is reactivated by a selenium-containing enzyme, thioredoxin reductase
What are sources of of vitamin E?
Vitamin E is synthesized by plants. High amounts in leafy greens, but also in seeds. Found in herbivore fat tissue (for carnivores) Many oils/ supplements would have tocopherols as preservatives.
What increases the requirement for vitamin E? Why?
The requirement for vitamin E increases with dietary fat and PUFA
The requirement is also coupled to selenium (as it is needed to reduce the oxidized vitamin E)
More Polyunsaturated acids, more sites vulnerable to oxidation. So more vitamin E is needed to donate their hydrogen atom to neutralize the compounds that will oxidize.
What else can cause decrease in uptake of vitamin E?
Excess vitamin A may antagonize other fat-soluble vitamins (vitamins E, K, D)
What is selenium?
Selenium is an essential mineral in all animals
It has several important functions but is primarily functions as a cofactor for
enzymes with antioxidant function
What is an enzyme that reduces lipid hydroperoxides to alcohols? Does it contain selenium?
Glutathione peroxidase (yes it contains selenium)
Where is selenium deficiency in cattle/ livestock found most commonly? Why?
- cattle/livestock raised on selenium poor soil
ie: Soils formed from volcanic activity, soil that pre-dates cretaceous period
ex: Pacific
Northwest, Northern California
Northeastern United States and Eastern Canadian
provinces
What is vitamin E and selenium deficiency called?
vitamin E and selenium deficiencies are called
‘white muscle disease’
What are clinical signs of white muscle disease?
- Muscle degeneration/ necrosis
- Acute extreme weakness
- The condition may affect the glottis and pharynx resulting in
secondary aspiration pneumonia
-Can cause cardiac failure and death
What are some pathological lesions of patients with white muscle disease?
White muscle disease causes muscles to be swollen and
edematous
White streaks in the muscle are highly characteristic of this
pathology
The result of oxidation
What is the other name of white muscle disease?
Zanker’s necrosis
Why is selenium important in canine and feline nutrition?
- Needed for testosterone and sperm function, as well as normal thyroid function.
What is copper? What can you see with copper deficiency?
Copper is a strong oxidant. In copper deficiency you can see anemia, decreased immune function.
Can also cause hypopigmentation ( since it is a cofactor for tyrosine which then cant convert to melanin)
Can also cause physitis, inflammation and abnormal maturation of the growth plates ( since it is a cofactor for lysyl oxidase, an enzyme important for collagen maturation)
What can you see with excess of copper?
Copper excess stores in the liver, can
cause liver failure in some cases
Copper hepatopathy- Certain breeds are more predisposed to copper hepatopathy.
What can interfere with copper absorption?
High sulfur or high molybdenum soil may interfere with copper absorption
Also Thiomolybdate complexes with dietary copper ions
TRUE or FALSE: Many forages in the US are adequate at meeting copper requirements in live stock
FALSE:
Many forages in the US are inadequate to meet copper requirements in livestock
Copper supplementation is common in many feeds for production animals in the US, Australia, NZ
What is vitamin K important for?
Vitamin K: important for coagulation
Vitamin K is an important cofactor for the synthesis of blood clotting factors
II, VII, IX, and X in the liver
What are the 3 types of vitamin K and where are they found?
Phylloquinone (K1) is present in
plants (leafy greens)
Menaquinone (K2) is produced by
the gut bacteria [this is why most
foods do not require added vitamin
K]
Menadione (K3) is a synthetic
supplement
What occurs in warfarin posioning and how would you treat it?
Vitamin K treatment is required in anticoagulant (warfarin) poisoning
- Inhibits vitamin K dependent clotting factors
Why is supplementation of vitamin K not required in normal circumstances? What circumstances will you need supplementation? Why?
Since menaquinone is synthesized by the gastrointestinal microflora,
supplementation is only required in specific conditions
- Rodenticide toxicity (warfarin)
- Severe liver or intestinal disease
- In livestock- moldy sweet clover (contains dicumerol) ( fungal organisms can metabolize cumerin to dicumerol)
- These compounds interfere with the synthesis of the vitamin K dependent clotting
factors
What can be supplemented to help increase the production of clotting factors
Vitmain K3
What are some things you can see in patients who have eaten rodenticide?
Spontaneous bleeding
epistaxis
petichie
What other instance (in cats) may their be a deficiency of vitamin K?
Vitamin K deficiency has also been
described in cats fed a diet that contains
fish
- Mechanism is unclear
Therefore, fish diets in cats do require
vitamin K supplementation
What is vitamin D? What are the roles of vitamin D?
Vitamin D is a fat-soluble vitamin that is involved in calcium, phosphorus and
bone metabolism.
Vitamin D has many additional roles and in fact has a nuclear vitamin D
receptor
- A transcription factor that regulates the expression of more than 900 genes
- Many animal species can use UVB light to synthesize vitamin D3
What are the other forms of Vitamin D and where are they found?
Vitamin D2 (ergocalciferol) is a plant/fungal derived form
Vitamin D3 (cholecalciferol) is animal derived (milk, meat egg)
What are the steps of hydroxylation of vitamin D?
The first- in the liver, converts vitamin
D to 25-hydroxyvitamin D [25(OH)D],
also known as calcdiol
The second is in the kidney which
results in the active form of vitamin D
[1,25 (OH)2D] or calcitriol
What is the role of calcitriol?
- Calcitriol promotes elevation of plasma calcium and phosphate levels, which are required for mineralization of bone.
- Calcitriol stimulates intestinal
calcium absorption throughout the
entire length of the intestine - With PTH, calcitriol promotes mobilization of calcium from bone
- Increases reabsorption of calcium in the distal tubules in the kidneys
Why does PTH and calcitriol regulate the mobilization of calcium from bone?
Narrow range of safety for calcium so it helps us to regulate it/ calcitriol + PTH
What is required to activate vitamin D? How must dogs and cats receive vitamin D?
Vitamin D activation requires a functioning kidney. Reduced activation in kidney disease
Dogs and cats cannot synthesize vitamin D in the skin (no precursor), so it must be provided in the diet
What can you see with vitamin D deficiency?
- Abnormal growth plate closure
- Long bone deformity
- Lack of mineralization
What can happen with excess vitamin D? How can a patient be given excess vitamin? Why?
- Vitamin D excess can be lethal and it is even used in some rodenticides
- Vitamin D is of a narrow safety range so excess is not uncommon
- With excess of vitamin D you can see hypercalcemia and hyperphosphatemia
- This can cause soft tissue mineralization, kidney injury and hypercalcemia. Hypercalcemia can also result in uroliths, neural signs and more.
What are the water soluable vitamins?
Vitamin B and C
What water soluable vitamin is commonly deficient in dog and cat food? What animals food is it normally not deficient in? Why?
Thiamine (vitamin B1) is a vitamin that is commonly deficient in dogs
and cat food as well as swine
B vitamins are synthesized by the GI microbiota in foregut and hindgut
fermenters (horses, ruminants)
Vitamin B12 (cobalamin) requires cobalt
It is relatively temperature sensitive and degrades easily
- Thiaminase- an enzyme that is found
in some raw fish /shellfish will also break down thiamine and is an antivitamin,
What is the role of B vitamins and what is the consequence of thiamine deficiancy?
B vitamins are vital for cellular energy metabolism . The brain has a high demand for
energy. Cats with thiamin deficiency have
characteristic neurological signs (head drop) and cardiac signs. Diet change can resolve symptoms ( raw fish/shellfish diet can cause this)
Thiaminase can also be a problem in ruminants. Changes of rumen microflora as a result of diet change or intake pattern can cause an increase in growth of Bacillus thiaminolyticus This can cause neurological signs in ruminants:
aimless wondering, stargazing, blindness
ie. CCN: Cerebral-cortical necrosis /
polyencephalomalacia
What is the role of iodine?
Iodine is key micromineral for the thyroid hormones triiodothyronine (T3) and thyroxine (T4)
Iodine deficiency would result in an enlargement of the thyroid gland= goiter + decreased thyroid function
It is reversible with iodine supplementation
Who was the first requirement of iodine documented about in veterinay medicine?
Budgies
What are the consequences of iodine deficiency?
Iodine deficiency would result in an enlargement of the thyroid gland= goiter + decreased thyroid function. Can obstruct airways and be a life-threatening emergency!
What are minerals?
There are multiple essential minerals
are required in the diet
Minerals may interact between them
to affect absorption and/or
metabolism
Some minerals can be provided in
excess and cause negative effects on
health or nutrient absorption
What are vitamins?
Vitamins are organic compounds that
have various functions
Some vitamins are essential in certain
species and not others
Vitamins differ in their solubility:
water soluble vs. fat soluble
