Thiamine
- Created by: faqihah21
- Created on: 15-05-24 15:23
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- Thiamine
- Functions of thiamine
- Oxidative decarboxylation reactions (CHO metabolism)
- essential role in deCO2 of alpha-keto acids
- Pyruvic acid depend on deCO2 to convert into Acetyl CoA
- a-ketoglutarate depend on deCO2 to convert into succinyl CoA
- essential in the TCA cycle
- essential role in deCO2 of alpha-keto acids
- pentose phosphate pathway
- only mechanism for ribose synthesis
- essential role in neurophysiology
- independent of its co-enzyme function
- could synthesize fatty acids, neurotransmitter or Na transport
- CHO metabolism
- Oxidative decarboxylation reactions (CHO metabolism)
- functional form is thiamine pyrophosphate
- requirements
- difficult to determine in ruminants, horse can absorb 25% from large intestine and supplement for monogastric
- requirement for ruminants - 1-2 mg/kg feed. cereals are rich source of thiamine 2mg/kg. dried brewer yeast >90 mg/kg
- not deficient = microflora synthesis + whole grain based feeds
- influence by diet composition and metabolic status - more CHO, more thiamine requirement. Fats and proteins - thiamine sparing
- proportional to size and age
- small hens - more than large breeds
- older animals have more requirement
- difficult to determine in ruminants, horse can absorb 25% from large intestine and supplement for monogastric
- Deficiency
- beri-beri in humans
- polyneuritis in poultry
- muscle paralysis reflexed legs and head back
- Pigs - reduce feed consumption, body weight gain and vomiting
- anorexic
- late stage deficiency = neurophysiological problems (common in all mammals)
- Thiamine responsive condition
- Cerebcorticonecrosis (CCN) in UK
- Development
- Polioencephalomalacia (PEM) in USA
- have lesions in both cerebral hemispheres
- acute and mild form
- give thiamine treatment for recovery
- low thiamine margin - reduce thiamine in tissue and high circulating lactate and pyruvate
- acidosis/low rumen pH
- potentiated by thiaminases in diet (thiamine antagonists that inhibit thiamine activity)
- high level of thiaminases = thiamine deficiency
- Development
- Polioencephalomalacia (PEM) in USA
- affect young ruminants - 4 months, 2 years old in sheep and goats 2-7 months
- Symptoms
- neck flexing, spasms, blindness, convulsions then death
- Cerebcorticonecrosis (CCN) in UK
- Thiamine responsive condition
- require CHO for CNS metabolism
- Young ruminants
- weakness, uncoordinated, arrhythmia and possible death
- Functions of thiamine
- Thiaminases - compete with thiamine
- found in raw fish or moldy food
- requirements
- difficult to determine in ruminants, horse can absorb 25% from large intestine and supplement for monogastric
- requirement for ruminants - 1-2 mg/kg feed. cereals are rich source of thiamine 2mg/kg. dried brewer yeast >90 mg/kg
- not deficient = microflora synthesis + whole grain based feeds
- influence by diet composition and metabolic status - more CHO, more thiamine requirement. Fats and proteins - thiamine sparing
- proportional to size and age
- small hens - more than large breeds
- older animals have more requirement
- difficult to determine in ruminants, horse can absorb 25% from large intestine and supplement for monogastric
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