Energy Associated B-Vitmains

Question 1

energy associated vitamins

Answer 1

• thiamin, riboflavin niacin panthenate biotin
• involved extensively in CHO AA and lipid metabolism as components of coenzymes
• coenzymes - small organis molecules, required for catalytic activity of enzymes

Question 2

general principles

Answer 2

• all 5 energy releasing vitamins are absortion by; passive diffusion at high levels in the gut, sodium dependent active transport at low levels in the gut
• excesses are excreted in the urine
• toxicity is rarely a problem
• storage is limited and they must be provided regularly

Question 3

thiamin or thiamine B1

Answer 3

• active thiamin is thiamin diphophate (TPP)
• thiamine diphosphate is a coenzyme in reactions involving removal of CO@
• an essential cofactor of multiple mitochondiral dehydrogenad=se complexes

Question 4

thiamine deficiency

Answer 4

• neural disorders - lack of thiamin causes brain damage, severe edema severe wasting of the lower limbs
  beriberi = common in SE asia because of polished rice diets (diet lacks thamin and riboflavin)
• rice bran contains thiamin and riboflavin
• primary cause of infant mortality in some regions

Question 5

thiamine deficieny in ruminants

Answer 5

• high sufate increase the metabolic demanf for thiamine
• causing poliencephalomalacia

Question 6

riboflavin B2

Answer 6

• functions as part of two coenzymes (Fad-flavin adenine dinucleotide, FMN flavin mono nucleotide)
• these two coenzymes are crucial to glucose and fatty acid oxidation

Question 7

riboflavin deficiency

Answer 7

• meat, especially liver, green leafy veggies
• relatively common vitamin deficient since it is low in cereals and legumes used for most monogastrics diets
• requirements are increased in high fat diets
• riboflavin deficiency does not lead to life threatening contitions
• symptoms = stomatitis glossitis seborrhea and photophobia
• in chickens causes curled toe paralysis
• other species have no specific symptoms

Question 8

niacin

Answer 8

• niacin is the genetic name for nicotinis acid and nicotinamide
• both may act as a source of the vitamin
• tryptophan can be converted into nicotinamide and can replace some of the requirement for niacin bu this pathway is very inefficient (60 mg tryptophan equals only 1mg of niacin in humans)
• conversion of Trp to niacin is especially inefficient in poultry
• sometimes need to add niacin to ruminant diets especially when using urea

Question 9

niacin deficieny

Answer 9

• pellagra in humans - diarrhea dermatitis dementia and death, leading cause of mental illness at the turn of the century
• pellagra means rough skin
• initially scientists believed it was a bacterial disease

Question 10

pellagra

Answer 10

• to produce a niacin deficiency requires a diet low in both niacin and tryptophan
• corn based diets meets this requirement
• corn protein is low in tryptophan

Question 11

biotin

Answer 11

• functions as a CO2 carrier in carbon dioxide fixation and decarboxylation
• biotin enzymes : pyruvate carboxylase Acetyl CoA carboxylase
• biotin is important in fat synthesis
• polyunsaturated fatty acids increase biotin requirments

Question 12

biotin deficieny

Answer 12

• hair loss dermitis and foot cracking depressioj hallucinations and muscle pain
• raw egg whites contain a protein called avidin which bind biotin making it unavaulable to the host

Question 13

pantothenuc acid sources

Answer 13

• whole grains (lost upon processing)
• animal liver, kidney
• fish shellfish
  -yogurt

Question 14

pantothenic acid deficieny

Answer 14

• deficiency of patothenic acid results in impaired fat synthesis
• deficiency symptoms include : dermatitis, goose stepping