ansc314 - water soluble vitamin C & thiamin

water soluble vitamins

• tend to be absorbed in s. intestine & circulated → liver in blood

• tend not stored in body

• often added to foods (fortification) / when added in certain amts, foods can be labeled ‘enriched’

• easily destroyed during cooking and storage

foritifed foods

have nutrients added to them that don’t naturally occur in the food

• ↑ nutrition & health benefits

enriched foods

means nutrients were lost during processing are added back

• refined grains are enriched (wheat flour)

• restore og vitamin levels

vitamin C

ascorbic acid

• mostly water & vit C

vitamin C structure

acidic

• least stable of all vitamins (easily oxidized/reduced)

  • good for rxns

• ease of oxidation basis of its biological function

vit C summary

• L-ascorbic acid (no scurvy)

• water soluble

• sources

  • citrus fruits

  • green, leafy veggies

  • synthesized by some animals

vitamin C roles

• antioxidant & reduction of vit E

• collagen synthesis & wound healing

  • hydroxylation of proline & lysine in collagen

• reducing properties:

  • Fe³⁺ → Fe²⁺

  • Cu²⁺ → Cu⁺

vitamin C synthesis

• can’t synthesize vit C

  • humans, non-human primates, guinea pigs, teleost fish, birds

    • dogs & cats can synth. vit C

• UDP - uridine diphosphate - nucleotide sugar

• 
  

vitamin C radical protection

vitamin C recharge

• vit C helps prevent lipid form oxidizing (reducing agent)

  • Fe²⁺ - cofactor

• vit C donates e^-. → Fe³⁺ (reduce) → Fe²⁺

  • enzyme to be active, needs to be in reduced form

vitamin C/E reduction

• remember: vit E, selenium, glutathione reductase

• vit E oxidized doing its job → vit C (oxidized) reduces vit E (reduced) → glutathione (GSH) reductase (oxidized) reduces vit C (reduced) → NADPH reduces glutathione reductase

  • cycle to keep vit E going

vitamin C & glutathione reduction

• remember: vit E, selenium, glutathione reductase, NADPH

• ascorbate (vit C) helps regenerate vit E

  • GSH helps regenerate vit C

    • NADPH helps regenerate GSH

• if see an “H” → reduction

glutathione (GSH)

part of some enzymes (glutamate, cys, glycine)

• glutamate linked to cysteine by R-group (COOH)

NADPH

reduced form of NADP+

• reduces GSH to keep cycle going

collagen synthesis

vit C

• most abundant connective tissue on body

  • primary building block & tensile support system for connective tissues

    • if no vit C → weak

• OH groups allow formation of crosslinks between collagen strands

application

• connective tissues ↑ rigid

  • tendon should be strong in animals (beef) so you can lift cattle by Achillies tendon to drain blood

    • ↑ tendonous → ↑ cross linked needed connective tissue needs to hold tension

collagen hydroxy-proline/lysine synthesis

norepinephrine synthesis

vitamin C deficiency

• scurvy

• poor wound healing

• gum lesions, spongy gums and bleeding

• loosening of teeth

• scoliosis (bone matrix)

• termination of bone growth

• joint pain & swelling

• increased sensitivity in extremities

• vomiting of blood & bloody stools

• edema of chest & stomach

• cerebral hemorrhage & capillary fragility

B vitamin energy metabolism

• all B complex vitamins critical to mitochondria function

  • most uses B vit as cofactor

  • “w/o B vit → mitochondria dead → we dead”

pyruvate dehydrogenase complex

thiamine (B1)

vitamin B1

• water soluble

• 1st vitamin discovered

  • beri-beri in humans (2600 BC) → weak-weak sheep (walk like)

• responsible for odor associated w/ vitamins (sulfur)

thiamin sources

• ruminant microbes → ↑ B complex vit. synthesis

  • ↓ dietary requirement

• monogastric ↑ dietary requirement (B vit)

• concentrated in growing areas of roots, leaves & shoots

• bacteria synthesize thiamin (rumen & gut bacteria)

• animal products

  • egg yolk, liver, kidney, pork muscle

• commercial supplement → thiamin-HCl

thiamin (B1)

• thiamin → thiamin pyrophosphate (TPP)

  • w/ help of ATP → AMP (TPP-synthetase)

thiamin pyrophosphate (TPP)

• 80% total in body

thiamin (TRPP) functions

• vit B1 needed for glucose oxidation & krebs cycle activity

  • NADPH - energy currency

  • acetyl CoA - carbon substrate for synthesis of free FA

    • 3 C → 2 C | loss of C → spits out CO₂

compound synthesis

• no vit B1

  • impaired glucose oxidation, lipid production, pentose phosphate

• acetyl-CoA

  • provides E & builds fats, hormones, steroids

  • precursor for any lipid intermediate

thiamin complex locations

thiamin utilization factors

• Amprolium (coccidiostat)

  • inhibits absorption of Thiamin from intestine

  • blocks phosphorylation of Thiamin → TPP

• Thiaminase (enzyme) activity destroys Thiamin activity by altering the structure of vitamin

  • “Chastek paralysis” – especially mink, fox, etc.

    • feeding raw fish that has a THIAMINASE

    • certain bacteria & molds also produce THIAMINASES

    • bracken fern poisoning in Horses results from THIAMINASE activity

amprolium

a thiamin analogue that prevents thiamin use by coccidia

• protozoan common in poultry, swine, calves

thiamin (B1) requirements

requirements in some species difficult to establish

• ruminant

  • synthesis by microbes in rumen

  • BUT, ↓ bacterial synthesis when ↑ concentrate (corn) diets are fed

• monogastrics

  • bacterial synthesis too far down intestinal tract for Thiamin to be absorbed

• horses

  • only 25% of free thiamin is absorbed from cecum

• humans & most species (except ruminant and horse)

  • bacterial thiamin synthesis & absorption makes little contribution to body needs

thiamin deficiency

acetyl CoA

precursor for acetyl-choline

• important for brain

  • neurotransmitter

  • if no B1 & glucose → end up w/ neurological disorders

thiamin deficiency symptoms

• liver

  • fatty degeneration & hemorrhages (bleeding)

• blood

  • lactic acid accumulation

• CNS

  • Polyneuritis (inflammation of nerves) → numbness, tingling, incoordination

  • Poultry

    • incoordination (ataxia)

    • progressive paralysis leading to death

    • star-gazing, curled back neck

  • Cattle, sheep and goats

    • Polioencephalomalacia (necrosis of brain)

• skin - edema, cyanosis

• muscle

  • degeneration and fiber swelling

  • muscle weakness, lactic ac

polyneuritis

thiamin deficiency in chickens

• curled neck

• frequent convulsions

• emaciation

polioencephalomalacia

thiamin deficiency in sheep

• also in cattle & goats

rolling disease

thiamin deficient rat