Vitamin A

Question 1

What is vitamin A active as?

Answer 1

alcohol, aldehyde, acetate, palmitate, and acid

Question 2

What does retinoic acid not fulfill the requirements for?

Answer 2

visual purple and reproduction

Question 3

What is the most popular synthetic form?

Answer 3

vitamin A palmitate

Question 4

Vitamin A occurs only in _____

Answer 4

animals (carotenoids in plants)

Question 5

Where is the highest levels of vitamin A found in the body?

Answer 5

the liver
-fish liver oils are very high

Question 6

Colostrum contains __________ A as other milk

Answer 6

10x as much

Question 7

What improves absorption of vitamin A?

Answer 7

bile salts and dietary fat

Question 8

Vitamin A formula

Answer 8

C20H30O (Retinol)

Question 9

Plays a role in the __________

Answer 9

visual purple cycle

Question 10

Maintenance of ________

Answer 10

normal epithelium (normal = columnar; deficiency = squamous)

Question 11

Needed for normal ___________ function

Answer 11

bone (slow osteoblast differentiation if deficient)

Question 12

Can cause ___________

Answer 12

nervous symptoms and blindness

Question 13

What happens to cerebral spinal fluid pressure in vitamin A deficiency?

Answer 13

pressure increases

Question 14

Necessary for normal ___________

Answer 14

reproduction

Question 15

Vitamin deficiency causes

Answer 15

-reduced appetite
-night blindness
-xerophthalmia (dry eye condition)
-runny eyes of cattle and sheep (copious lacrimation)
-Dried up tear glands in chickens
-increased keratinization of epithelium
-increased respiratory problems
-vaginal/repro tract problems
-favors formation of kidney stones
-congenital malformations in certain soft tissues
-liver and kidney damage
-diarrhea
-testicular degeneration (reversible)

Question 16

Hypervitaminosis (toxicity)

Answer 16

-skin thickening
-interference with bone development
-prolonged prothrombin time
-increased cerebrospinal fluid pressure (hydrocephalus)
-lowered plasma cholesterol
-resorption of fetus
-decreased appetite

Question 17

What is converted into vitamin A?

Answer 17

carotene that isn’t absorbed into the bloodstream

Question 18

Where is carotene converted into vitamin A?

Answer 18

intestinal wall

Question 19

Rats, goats, sheep, and pigs are known as __________ in terms of carotene

Answer 19

white fat species

Question 20

Cows and horses are known as ____________ in terms of carotene

Answer 20

yellow fat species (because plasma containing carotene may by stored in liver and fatty tissues)

Question 21

Where is vitamin A stored?

Answer 21

liver (70-93% of vitamin A found here)
-remainder is in fat deposits, kidneys, adrenals, and other organs

Question 22

What do liver stores act as?

Answer 22

a buffer against subsequent dietary inadequacies

Question 23

All-trans relative biopotency %

Answer 23

100

Question 24

13-cis relative biopotency %

Answer 24

75

Question 25

11-cis relative biopotency %

Answer 25

24

Question 26

9,13-di-cis relative biopotency %

Answer 26

24

Question 27

9-cis relative biopotency %

Answer 27

21

Question 28

11,13-di-cis relative biopotency %

Answer 28

15

Question 29

Sources of vitamin A

Answer 29

-fish oils -egg yolk -liver -milk fat

Question 30

Sources of carotenes

Answer 30

high in green leafy plants -decreases due to storage -rain damage and oxidation of sun loses up to 80% during first 24 hours of curing

Question 31

General requirement of vitamin A

Answer 31

20-100 IU/kg BW (5x for poultry)

Question 32

What increases stability of vitamin A?

Answer 32

-coating with gelatin -adding the antioxidant vit. E

Question 33

What destroys vitamin A?

Answer 33

-certain metals -high temperatures