export_water soluble vitamins Flashcards
T or F: Body reserves of water-soluble are more extensive than those of fat-soluble vitamins.
False. Water-soluble reserves are less
B vitamin deficiencies most typically occur as (multiple, single) vitamin deficiency, unlike fat-soluble vitamins.
multiple
Water-soluble vitamins have (higher, lower) toxicities than fat-soluble vitamins.
lower
T or F: Ruminants with a functional rumen do not require a dietary source of water-soluble vitamins and therefor do not have a “metabolic need” for water-soluble vitamins.
False; ruminants have a metabolic need
Vitamins important to central pathways of E metabolism
Niacin (B3), Riboflavin (B2), Thiamin (B1)
generic for nicotinic acid and nicotinamide
vitamin B3 (Niacin)
used in formation of pyridine nucleotide coenzymes, nicotinamide adenine dinucleotide and its phosphorylated form (NADP)
Niacin (B3)
NAD used in:
ADP-ribosylations of proteins; poly-ADP-ribosylated proteins function in DNA repair
Pharmacological niacin use
reduce plasma cholesterol and TG; “antilipolytic” effect = inhibits adipose release of lipid
Plant sources of Vit B
cereals, legumes, yeast; bran of cereals (brown vs white rice)
Some niacin is synth from essential AA:
tryptophan
“niacin equivalence”
tryptophan
T or F: Trptophan conversion to niacin is essential in cats.
False; negligible
Causes of niacin deficiency
poor diets and condidtions affecting tryptophan-niacin conversion
Signs of Niacin deficiency (3 Ds)
dermatitis, diarrhea, dementia
dermatitis, diarrhea, and dementia are signs of:
vitamin B3 deficiency
“Loading test” results - nicotinamide amount recovered in urine after an oral load of nicotinamide
vitamin B3 (niacin) deficiency
Used in formation of “flavocoenzymes” (FAD and FMN)
riboflavin (B2)
Plant sources of riboflavin
green vegetables, not cereals;
effect of UV light on riboflavin
Riboflavin inactivated by UV light
Substantial milk secretion occurs
riboflavin absorption and metabolism
Causes of riboflavin deficiency
when grain is major source of food
Signs of B2 deficiency
growth problems, skin problems, eye problems, anemia, neuropathy
“Enzyme stimulation test” used for:
detecting vitamin B2 deficiency
Stimulation of reduction of oxidized glutathione by the erythrocyte enzyme ertyrocyte glutathione reductase in presence of FAD
Niacin deficiency
cofactor for catabolism of CHO and AA metabolism for E production
thiamin
Causes of thiamin deficiency
cooking (destroyed by high temperature), thiaminases, agents that interfere with thiamin phosphorylation
Enzymes that destroy thiamin in raw fish, bracken fern, and horse-tail
thiaminases
Signs of B1 deficiency in Cats and dogs
reduced food intake, body weight loss, neuro changes
Signs of B1 deficiency in horses
incoordination to the point of falling and bradycardia d/t cardiac irregularity
Signs of B1 deficiency in cattle/sheep
neuro changes
Erythrocyte transketolase enzyme stimulation test is used to diagnose:
Thiamin deficiency (B1)
Vitamins of coenzymes important to AA metabolism
Folate, B12, B6, C
Sources of folate
green leafy vegetables, lima beans, citrus fruits, meats
Folate is concentrated in _____ where it is left over from _____.
RBC; erythropoesis
reduced food intake, BW loss, neuro changes (pupillary dilation) VENTROFLEXION of head could be signs of
thiamin deficiency
Methionine synthase is an enzyme dependent on:
B12
Methyl carbon from folate is transferred to homocysteine to form methionine by
methionine synthase
Megaloblastic anemia
large, hypochromic RBCs and deranged DNA synth in erythropoietic cells
Megaloblastic anemia is a sign of
folate deficiency
B12 is a cofactor of what 2 enzymes?
methionine synthase, methylmalonyl CoA mutase
Fxn of methionine synthase
remethylates homocysteine; demtheylates reduced methylated folate, making folate available for coenzymes
Methylmaolnyl CoA mutase
catalyzes conversion of methylmalonyl CoA to succinyl CoA; conversion needed in metabolism of some FA and AA
Folate main fxn
donating and receiving carbon units
Sources of B12
gut bacteria, coprophagy, ruminal bacteria
Synthesis of vitamin B12 requires
cobalt
Animal sources of B12
meat, dairy
Plant sources of B12
none
Absorption of B12 occurs in
ileum
“intrinsic factor” required for absorption of:
B12
Intrinsic factor produced by:
gastric mucosa, pancreas, salivary gland
Causes of B12 deficiency
low intake, maldigestion (disease), lacking vit B12 in methionine synthase
Signs of B12 deficiency
megaloblastic anemia; neuro disease (similar to folate)
Diagnosis of B12 deficiency
megaloblastic anemia; [B12]
Vitamin C is synthesized from:
glucose
Vitamin C main fxn
electron donor for enzymes;
a 6-carbon “lactone”
vitamin C (ascorbic acid)
Sources of vit C
fruits, vegetables; animal sources are POOR
Least stable of all vitamins
vitamin C
T or F: Dogs and cats do not require dietary vitamin C.
True
Dehydroascrobic acid is:
part catbolized oxalic acid, a substrate of uroliths (kidney and bladder stones)
Animals that require dietary vit C
primates, guinea pigs, some snakes and fish and birds
Cause of vit C deficiency
low dietary intake
Scurvy
human symptoms of vitamin C deficiency; SQ hemorrhages, joint pain, anorexia, edema, teeth loosening
