NUT 141 E3 Fxns/Deficiency/Toxicity

Vitamin A Function

Normal night vision

Hormone like growth factor

-cell proliferation/differentiation

-epithelial cell integrity

-bone growth and remodeling

Vitamin A Deficiency

Night Blindness

Xerophthalmia

Keratinization of respiratory epithelium

Ataxia/CNS disorders

Reproductive failure

Vitamin A Toxicity

Anorexia

Skin thickening

Hemorrhaging

Hair loss

Decreased bone strength

Death

Vitamin D Function

Elevates plasma Ca (and P)

-Active form 1,25-(OH)2-D

-Permits normal bone mineralizatin

-Prevents tetany

Stimulates innate immunity and suppresses autoimmune responses

Vitamin D Deficiency

Osteomalacia (soft bones/rickets)

Osteoporosis (porous, brittle bones)

Vitamin D Toxicity

Abnormal deposition of Ca in soft tissue

Vitamin E Function

Free radical scavenger/antioxidant

Vitamin E Deficiency

Nutritionla muscular dystorphy

Exudative diathesis in poultry

Encephalomalacia

Most signs partially relieved by Se but intensified by PUFA

Vitamin E Toxicity

Few reports

Vitamin K Functions

Normal blood clotting

Vitamin K Deficiency

Prolonged clotting times, hemorrhage, and death

Antagonists can cause deficiency signs

-Warfarin

-Dicoumarol

Vitamin K Toxicity

Only K3 is toxic, causing anemia, chest pains, shortness of breath

Thiamin Functions

Coenzyme in decarboxylases and dehydrogenases

IMPORTANT EXAMPLE: Pyruvate dehydrogenase...TPP=Thiamin Pyrophosphate

Thiamin Deficiency

Increased blood pyruvate and lactate

Beriberi in humans (numbness, enlarged hearth, edema, paralytic)

Polyneuritis in chicks (retraction of head)

Weak swimming and death in chinook salmon

Riboflavin Function

Component of coenzymes FAD(H2) and FMN(H2)

Riboflavin Deficiency

Paralysis in chicks (curled toes/leg sprawling)

Reduced growth rate

Niacin Function

Component of coenzymes NAD(H) and NADP(H)

Niacin Deficiency

Pellagra (diarrhea, dermatitis, dementia, death)

Reduced growth and appetite

Pantothenic Acid Function

Component of coenzyme A (as in acetyl-CoA)

Pantothenic Acid Deficiency

"Goose-stepping" in pigs (abnormal gait from nerve degeneration)

"Burning feet syndrome" in humans

Reduced growth rate

Rare bc vitamin is widely distributed (Pan=all)

Vitamin B6 Function

Coenzymes in all amino acid transaminases

Coenzymes in some AA decarboxylases, deaminases, and racemases

Vitamin B6 Deficiency

Convulsions

Demyelination of peripheral nerves

Swelling and fragmentation of myelin sheath

Vitamin B12 Structure

CONTAINS COBALT (CO)

Vitamin B12 Function

Component of coenzymes of methyltransferases

EXAMPLE: Methionine synthase partners with THF, regenerating methionine from homocysteine

Vitamin B12 Deficiency

Pernicious anemia in humans

Growth Failure

Relieved by methionine or tetrahydrofolate (THF)

Folacin Function

Component of coenzymes of methyltransferases

EXAMPLE: methionine synthase

Folacin Deficiency Signs

Anemia

Birth defects (ex. spinal bifida in humans)

Biotin Function

Components of coenzymes of carboxylases

EXAMPLE: pyruvate carboxylase in gluconeogenesis

EXAMPLE: acetyl-CoA carboxylase in FA synthesis

Biotin Deficiency

Scaly dermatitis and alopecia

Rare because requirement is low

Vitamin C Function

Reducing agent

EXAMPLE: Hydroxyproline and hydroxylysine synthesis

Vitamin C Deficiency

Scurvy

10% of undergrads are deficient

Vitamin C Essentiality

Non-essential in most mammals bc it can be synthesized from glucose

Essential in humans, primates, guinea pigs, and others that lack enzymes for synthesis

Choline Function

Component of membrane phospholipids

Component of neurotransmitter acetylcholine

Donor of methyl groups

Only water soluble vitamin which is not a coenzyme)

Choline Deficiency

Fatty liver

Perosis in chicks (slipped tendon)

Calcium Function

Component of hydroxyapatite in bone

Second messenger in cell pathways

Calcium Deficiency

Rickets/skeletal deformities

Calcium tetany/Milk fever (weakness, loss of appetite, muscle convulsions, heart failure)

Intensified by high P diet (inhibits Ca absorption)

Calcium Antagonism/Toxicity

Inhibition of Zn and other mineral absorption

Bone thickening (osteopetrosis)

Calcification of soft tissues

Urinary calculi

Phosphorus Function

Component of skeleton

Component of phospholipids, DNA and ATP

Phosphorus Deficiency

Rickets

Phosphorus Antagonism/Toxicity

Inhibition of Ca absorption

Excessive bone resorption

Lameness

Spontaneous fractures of long bones

Magnesium Function

Component of skeleton

Cofactor for many enzymatic reactions (all those involving ATP)

Binds to a stabilized structure of DNA

Magnesium Deficiency

Anorexia, reduced weight gain, hyperemia of ears

Grass Tetany (too high K to Mg ratio => Muscle twitching, incoordination, staggering, collapse, coma, death)

Intensified by high K (inhibits Mg absorption)

Magnesium Toxicity

Depressed feed intake

Diarrhea

Loss of reflexes

Cardiorespiratory depression

Depression of growth

Potassium, Sodium, Chlorine Function

Transport

Maintenance of osmotic pressure

Action potentials in neurotransmission

Component of buffers

Potassium, Sodium, Chlorine Deficiency

Reduced growth rates

Abnormal electrocardiograms (K)

Potassium, Sodium, Chlorine Antagonism/Toxicity

K inhibits absorption of Mg

Large dose of KCl causes death

Toxicity otherwise manifested rarely bc kidney regulates excretion

Sulfur Functions

Components of many organic molecules:

-Amino Acids

-Coenzyme A

-Mucopolysaccharides

-Biotin

-Thiamin

-Heparin

Sulfur Deficiency

Deficiency in organic compounds will create expected deficiencies for those compounds

None for inorganic s (no requirment)

Sulfur Toxicity

Polioencephalomalacia

Excess intake of S-containing organic compounds will create expected toxicities for those compounds

Other symptoms rare bc intestinal absorption of S is slow

Cobalt Function

Component of B12

Cobalt Deficiency

None per se...manifested as B12 deficiency

Cobalt Toxicity

Rare due to low intestinal absorption

Iodine Function

Component of thyroxine

Iodine Deficiency

Goiter

Reduced metabolic rate

Skin dryness and brittle hair

Reproductive failure

Iodine Toxicity

Goiter

Reduced egg production in chickens

Rare dude to apparently wide margin between normal dietary and toxic levels

Zinc Function

Component of many metalloenzymes:

-DNA plymerase

-Carbonic anhydrase

-Aalkaline phosphatase

Zinc Deficiency

Parakeratosis in swine

Reduced growth and feed intake

Zinc Toxicity

Rare due to apparently wide margin between normal dietary and toxic levels

Iron Function

Component of heme, which is in turn component of:

-Hemoglobin

-Myoglobin

-Cytochromes

-Catalase

Iron Deficiency

Anemia

Iron Toxicity

Diarrhea

Reduced growth

Reduced feed efficiency in animals

Iron overload disorder in humans

Copper Function

Component of:

-Cytochrome C oxidase

-Enzymes for elastin and collagen formation

-Ceruloplasmin

Also important in normal hair and wool pigmentation

Copper Deficiency

Anemia

Bone abnormalities

Steely wool in sheep (straight, hair like wool)

Sway-back in sheep (incoordination and ataxia)

Copper Toxicity

Hemoglobinuria(excess hemoglobin in urine) and death

Sheep and claves particularly susceptible

Manganese Function

Cofactor in various metalloenzymes

EXAMPLE: pyruvate carboxylase in gluconeogenesis

Manganese Deficiency

Skeletal abnormalities

Manganese Antagonism/Toxicity

Reduced Ca and P absorption

Other symptoms rare due to apparently wide margin between normal dietary and toxic levels

Selenium Function

Component of glutathione peroxidase

Component of other selenoproteins

Selenium Deficiency

Nutritional muscular dystrophy

Exudative diathesis in poultry

Most deficiency signs partially relieved by Vitamin E

Selenium Toxicity

Blind staggers (emaciation, loss of hair, sloughing of hooves, blindness) in grazing animals

Reduced egg production and increased birth deformities

Flourine

Prevents tooth decay

Molybdenum

Component of metalloenzymes

Silicon

Involved in initiating bone mineralization, but hard to demonstrate requirement outside of purified diets