Nutritional Biochem Exam 3

Water-soluble vitamins

vitamins C and all B-complexes

Fat-soluble vitamins

K.A.D.E (vitamins, A, D, E, and K)

Vitamin B1 - Thiamine - FUNCTIONS

• Part of coenzymes in many reactions

• Catabolism of sugars and amino acids

• Thiamine pyrophosphate (TPP)

Classic diseases associated with B1 - Thiamine

What is B1’s (thiamine) competitive antagonist/blocker/analogue

Amprolium

Thiamine Deficiency in cats: what are the two major etiologies?

• Cats fed fresh or frozen fish containing thiaminase

• Cats fed canned foods in which thiamine has been destroyed by overheating during canning process

What are the clinical signs of Thiamine Deficiency in cats?

• Anorexia

• Ataxia/muscle weakness, – e.g. ventroflexion of head

• Severe mydriasis

• Convulsions, coma and death

what is the major clinical form of thiamine deficiency?

Encephalopathy

Functions of B2: Riboflavin

Coenzymes:

• Flavin Mononucleotide (FMN)

• Flavin Adenine Dinucleotide (FAD)

• Energy Production. Cell Growth.

• Metabolic Reactions

Classic diseases of B2 deficiency

Ariboflavinosis

Mucous membranes in people

Curled toes due to dystrophia in the peripheral nerves, leading to paralysis

What is Beta-oxidation of Fatty Acids?

It is a cyclic degradative pathway where 2C units (acetyl CoA) are cleaved from carboxyl end

What is rxn 1 in Beta-oxidation of FA and its significance?

acyl CoA dehydrogenase

what are the products of one cycle of Beta-oxidation of FA?

• acetyl CoA

• 1 FADH2

• 1 NADH

Niacin

What are vitamers?

vitamins that have vitamin activity but are not the same molecule

ex: Nicotonic acid, *Nicotinamide*, Nicotinamide riboside

What is Nicotinamide adenine dinucleotide (NAD)?

coenzyme: carries electrons in redox reactions

Overview of glycolysis

• One glucose (6C) degraded to two pyruvate (3C)

• Fate of glucose depends on O2 availability

• Primary source of energy

B5 Pantothenic Acid Functions

• Part of Coenzyme A (CoA)

  • – Acetylation in many reactions

• Catabolism of sugars and amino acids

• Thiamine pyrophosphate (TPP

Sources of B5 Pantothenic Acid

Widely distributed in plant and animal foods,

so deficiency is unlikely.

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Classic diseases B5 Pantothenic Acid

• General ill thrift, skin, GI, and nervous system issues.

• Goose-stepping in pigs due to nerve degeneration

B6 Pyridoxine Functions

• Coenzymes involved in protein and N metabolism

• Most common sign of deficiency: Nervous System

Do water soluble vitamins have toxicity problems?

No

B7 functions Biotin Functions

• Coenzymes: CoA, amino acid metabolism, fat metabolism, transcarboxylation.

• The amount needed is small relative to the amount generally supplied in normal ingredients.

• Cattle and horses: Hoof health.

B9 Folic Acid functions

Involved in Vitamin B12 Metabolism

Classic B9 (folic acid) defiencies/disease

• Macrocytic hypochromic anemia

• Leukopenia

• Thrombocytopenia

Spina Bifida in Humans (Neural Tube Defect) - Supplement before and early in pregnancy

B12 Cobalamin

History and Fun Facts

Last Vitamin Discovered

First known as Animal Protein Factor

Rats and Coprophagy

Formed by Bacteria, Not Plants or Animals

Contains Cobalt

most animals gave a Vit B12 requirement

True or false ruminants have a Co(balt) requirement?

True

Do ruminants have a B12 requirement?

NO

Choline Functions

• Phospholipid synthesis (membranes, VLDL

• Acetyl choline formation (neurotransmitter)

• Transmethylation of homocysteine to methionine

• Platelet activation-clotting

Choline sources

Meat, Soy, Other Grains/Vegetables, Rumen Bypass Products

Choline deficiency

reduced all around; weight gain, rough hair coat, etc.

Vitamin C: Ascorbic Acid function

cofactor for many enzymes

• Collagen synthesis

  • Bone, teeth, cartilage, connective tissue, muscle

  • i.e. Scurvy

• Amino Acid metabolism

• Antioxidant activity

• Iron absorption

• Immune function

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Sources of Vitamin C

fruits and vegetables

Factors that affect vitamin requirements

Life stage, health/disease status, & species (ruminant vs. non ruminant)

How does life stage affect vitamin requirments?

growing animals have greater req./more susceptible to toxicity

Vitamin deficiency

lack of vitamins in quantities to support normal physiological Function

Vitamin toxicity

excessive quantities

Vitamin adequacy

Provide appropriate balance for each life stage but not over-supplement; stay within the optimum range

What are some that affect estimation of vitamin content and availability?

• Estimating content of foodstuffs is difficult because of cumulative errors made in estimating content and availability

  • Analytical/sampling error

  • Variation

  • Presence of bound forms

  • Storage/processing losses

• commercial foods are typically fortified

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Forms of vitamin A

What is B-Carotene?

It is a provitamin A

• 
  

Slide 37 cats

• Vision

• Cellular Differentiation

• Growth

• Reproduction

11-cis retinal converts light energy into a nerve impulse via

rhodopsin formation in the retina.

– Promotes mucin (in mucus) release of the corneal and

conjunctival epithelial cells

A 6-month-old, fully indoor, Labrador puppy fed a homemade diet presents with lameness, bowing of long bones, and delayed tooth eruption. Radiographs reveal reduced bone mineral density.

 

Rickets caused by inadequate exposure to sunlight and dietary vitamin D

Several cows in a herd die suddenly after being fed moldy sweet clover hay. Necropsy reveals widespread internal hemorrhage. You suspect which vitamin may be affected? 

 

Vitamin K

Which of the following species has a limited ability to convert β-carotene to vitamin A?

 

Cats

A 4-year-old domestic shorthair cat is presented with anorexia, ataxia, ventroflexion of the head, and dilated pupils. The owner reports feeding primarily canned tuna for the past several weeks

 

Thiaminase activity destroying vitamin B₁

A group of 8-week-old pigs suddenly develop weakness, reluctance to move, and several die acutely. Necropsy reveals pale streaks in skeletal and cardiac muscle (“mulberry heart disease”). This condition is associated with vitamin E and selenium deficiency. What is the primary mechanism leading to the observed lesions?

 

Reduced antioxidant defense allowing oxidative muscle damage