Vitamins Flashcards
beriberi
thiamin deficiency
Define vitamin
organic compound that is required in a very small amount
pellagra
niacin deficiency
rickets
vitamin d deficiency
scurvy
vitamin c deficiency
night blindness
vitamin a deficiency
fat soluble vitamins
A, D, E, K
water soluble vitamins
thiamin, niacin, pantothenic acid, pyridoxine, cyanocobalamin, folic acid, biotin, choline, ascorbic acid (vitamin c), riboflavin
vitamins synthesized by the rumen
water soluble vitamins and vitamin K
vitamin D synthesis
from precursor 7-dehydrocholesterol by skin exposure to UV light
animals that cannot synthesize vitamin C
primates and guinea pigs
forms of vitamin A
retinoids and carotenoids
beta carotene
form of vitamin a found in plants (stored hay and grain)
animals that cannot turn beta carotene into vitamin a
cats and mink
biological functions of vitamin A
- forms rhodopsin which is required for sight
- required by epithelial cells: skin, GIT, reproductive tract, bone growth, mucus membranes
- protection against disease
- protection against cancer/antioxidants
path of vitamin A absorption
IMC (active transport) > incorporated in chylomicron > liver
vitamin a deficiency
nyctalopia (night blindness)
xerophthalmia (toad skin)
reduced feed intake, edema, lacrimation, weakened immunity, death
poor bone growth
rarely occurs in adults because several years worth is stored in liver
vitamin A toxicosis
10x minimum daily requirement
bulging fontanelles, headaches, nausea, vomiting, visual disorientation, peeling skin
biological function of vitaminD
Ca and P homeostasis
-increases blood calcium by promoting resorption of Ca from renal tubule and bone stores
-increases enteric absorption of Ca through increased synthesis of Ca binding protein
-increases enteric phosphate absorption (independent of Ca)
-bone formation and mobilization
osteoporosis
loss of bone mass starting in third to fourth decade in females, fourth to fifth in males
sunshine and vitamin D
sunlight catalyzes the opening up of the cholesterol precursor, first hydroxylation occurs in liver and second on kidney
absorption and metabolism of vitamin D
absorbed from small intestine or synthesized on skin snd carried to liver
vitamin d deficiency
abnormal bone formation, all symptoms relating to Ca deficiency
rickets in young animals
osteoporosis in old
lameness, bowed and crooked legs, spontaneous fractures of the long bones
young poultry more susceptible than calves and pigs
can be used to treat milk fever
vitamin d toxicosis
rare in livestock
loss of Ca and P homeostasis
increased deposition of Ca in soft tissues
death from uremic poisoning from severe calcification of kidney tubules
vitamin E (tocopherol) biological function
anti-sterility vitamin, prevents resorption of fetuses and testicular degeneration
stabilizing cell membrane structure, functions with selenium, protects cell against adverse effects of free radicals
absorption and metabolism of vitamin E
-found in lipid fraction of plant seeds, limited amount in animal tissue, fruits and vegetables
-absorption in jejunum (20-40%) dependent upon micellar solubilization and presence of bile and pancreatic solutions
-transported to liver via chylomicron and to general circulation in VLDL
-all extra hepatic tissue take up vit E from VLDL
vitamin E toxicosis
one of least toxic vitamins
substitutes for 50% of selenium requirement
vitamin E deficiency
-reproductive failure: embryonic -degeneration and testicular atrophy
-encepholomalacia in chicks (abnormal softness of cerebral parenchyma) causes ataxia, spasms, paralysis
-exudative diatheis (in chickens) acculumation of fluid in subQ tissues, muscles, or connective tissue caused by leakage of plasma
-selenium can protect against
biological role of vitamin K
blood coagulation cascade
formation of clotting factors
prevent hemorrhage and lead to thrombus formation
foods containing vitamin K
green leafy vegetables
very low in fruits and grains
low to moderate in meats and dairy
phylloquinones
form of vit K synthesized in plants, has least biological activity
menaquinones
form of vit K synthesized by rumen microbes
menadione
synthetic form of vit K, highest biological activity
absorption and metabolism of vitamin K
-phylloquinone absorbed by energy dependent process in SI
-menaquinone and menadione absorbed via passive diffusion in SI & colon
-then incorporated into chylomicron, transported to liver, exported in VLDL
-menadione rapidly metabolized and excreted in urine
-phylloquinone and menaquinone excreted in feces via bile
tissue distribution of vitamin K
-natural sources readily taken up by liver but has short half life
-little vit K crosses placenta and little in milk, infants susceptible to hemorrhage
-no good long term storage
vitamin K deficiency
rare because of wide distribution in plant and animal foods and bacterial synthesis
increased blood clotting time
subQ hemorrhages
reasons an animal may need extra vit K
-chicks on coccidiostat sulfaquinoxaline
-prevents coprophagy in rats and pigs
-mycotoxins in grain
-broad spectrum antibiotics eliminate beneficial bacteria
-vit K antagonists: sweet clover (dicoumarol), warfarin (rat poison)
osteocalcin
vit K dependent gla proteins found in rapidly growing bone, regulation of incorporation of calcium phosphates into bone
second most abundant protein in bone
vitamin K toxicosis
menadione toxic to skin: chest pains and shortness of breath
phylloquinone: essentially nontoxic
biological function of thiamin / B1
-functions in oxidative decarboxylation reactions of krebs cycle
-involved in nerve transmission and/or excitation, CNS requires thiamin as cofactor for glucose
absorption and metabolism of thiamin
-found in most animal tissues (phosphorylated), cereal grains and legumes (free)
-absorbed from small intestine by passive diffusion at high concentration, active transport at low concentration
-stored in small quantities in tissue/liver
-pigs store large quantities in muscle
thiamin deficiency
-seen when polished rice staple food, alcoholics
-activity can be destroyed by processing and preservatived\s
-anorexia, enlargement of heart, numbness of extremities, edema of feet, paralysis
-ataxia and mental confusion in alcoholics
-polyneuritis in chicks, rats walk in circles, ventroflexation of head and neck
-many foods (raw fish, bracken fern) contain enzymes that split thiamines rendering it unavailable
thiamin toxicosis
-relatively non toxic, lethal effects at 1000x dietary requirements
-blocks nerve transmission, curare like symptons
riboflavin / B2 natural source
milk, whey
biological function of riboflavin
component of FMN and FAD
transfer of electrons in ETC
absorption and metabolism of riboflavin
absorbed in SI via active transport
immunoglobins involved in transport
little storage in body, readily excreted in urine
riboflavin deficiency
causes impaired growth and reduced feed efficiency
curled toe paralysis in poultry
dermatitis, conjunctivitis, malformations, still births
riboflavin toxicosis
very low toxicity level
niacin natural sources
both plant and animal origin
most in plants is bound
meat, milk, fish has no bound form
very heat and light stable
niacin biological function
redox reactions as two electron transporters
-NAD/NADH transports electrons for metabolic intermediates to mitochondrial ETC
-NADP/NADPH serves as reducing agent in biosynthetic processes
-critical for mitochondrial respiration, metabolism of carbs lipids and AAs
absorption and metabolism of niacon
-simple diffusion across intestinal mucosa
-nicotinic acid converted to nicotinamide and incorporated into coenzyme (NAD/NADP)
-nicotinamide synthesized from tryptophan
-excess excreted in urine
species with high niacin requirement
cats, low efficiency of tryptophan to niacin conversion
niacin deficiency
-anorexia, reduced growth, muscular weakness, digestive disorders, diarrhea, poor feathering
-known as Black Tongue in dogs and Pellagra in monogastrics
-requirement determined by efficiency of metabolic converstion to TRYP to niacin
niacin toxicosis
low toxicity
pellagra causes and symptoms
3 Ms: diet of meat (fat), molasses and (corn) meal
4 Ds: causes dermatitis, diarrhea, dementia, death
castles collar: bright red welts around neck
nixtamalization
mixing cornmeal with water to release bound niacin to make it bioavailable
understood by aztecs and mayans
pantothenic acid biological function
component of coenzyme a
acyl group transfers, CoA synthetase, acyl carrier protein
pantothenic acid absorption and metabolism
natural coenzymes hydrolyzed in intestine to pantothenic acid, absorbed, circulated, cellular enzymes convert into CoA
excess excreted in urine
pantothenic acid natural sources
widely distributes in feeds as a mixture of coenzymes
pantothenic acid deficiency
decreased metabolism
poor growth, dermatitis, hemorrhaging of adrenal cortex, reduced immunity
goose stepping in pigs
pantothenic acid toxicosis
no adverse responses have been documented
pyroxidine natural forms
-unstable in heat and light
pryidoxol (inactive)
pryidoxal
pyridoxamine
-phosphorylated to be active
-found in yeast, liver, muscle, milk, vegetables, cereal grains
pyridoxine biological function
-coenzyme to many enzyme systems in nitrogen metabolism
-cofactor for mobilization of glycogen stores
-required for RBC formation
-function of many hormones (GH, insulin, sex hormones)
pyroxidine absorption and metabolism
-absorption of free forms in SI by passive transfer
-little storage within body
once ingested must be converted to active form (PLP and PMP) which requires FMN, FAD, NAD > deficiency of riboflavin or niacin results in decreased active pyroxidine
pyroxidine deficiency
-unlikely because of wide distribution in feed
-nervous system convulsions, demyelination of nerves, skin lesions on feet, face, ears, reduced immunocompetence in offspring of depleted females
pyroxidine toxicosis
essentially non toxic
biotin natural sources
widely distributed in low concentrations in plant and animal tissue
biotin biological function
metabolic carboxylation reactions
ex. pyruvate carboxylase (gluconeogenesis), acetyl CoA carboxylase (FA synthesis). propionyl CoA carboxylase (conversion propionyl CoA to succinyl CoA)
biotin absorption and metabolism
absorbed in SI, little stores in body
biotin deficiency
-commonly occurs in poultry
-dermatitis and perosis (slipped tendons)
-can be caused by eating raw egg (protein avidin in egg white binds to biotin, strongest bond known in nature), avidin/biotin complex commonly used in lab immunoassays ex. ELISAs
-slatted floors can increase symptoms, prevents coprophagy
biotin toxicosis
relatively nontoxic, 4-10x nutritional requirement tolerated, perhaps even higher
folic acid natural sources
-widely distributed in plants and animals
-folacin any compounds with folic acid activity
-active form tetrahydrofolate/THF (reduced form)
folic acid biological function
-one carbon transfer reactions
-required for synthesis of purines, pyrimidines, glycine, serine
-choline and methionine metabolism
folic acid deficiency
-more likely when antagonists present in diets, ex, wide spectrum antibiotics, sulfa drugs used as coccidiastats in chick feed
-macrocytic hyperchromic anemia (large, immature RBC), leucopenia (low WBC count), thrombocytopenia (low platelet count), impaired biosynthesis of purines and pyrimidines
folic acid absorption and metabolism
-synthesis and absorption in intestine
-actively absorbed from GIT, carried to all tissues of body
-liver main site of conversion of folicin to THF
folic acid toxicosis
essentially non toxic, no adverse affects documented
