Vitamin A and Carotenes

Question 1

Vitamin A refers to several compounds that possess activity of ______ and ______.

Answer 1

retinol and retinal

Question 2

What are the functions of Vitamin A?

Answer 2

Cell differentiation and gene transcription, vision, embryonic development and repro, skin health, bone growth, hematopoiesis, immune modulation, and anti-oxidant activity

Question 3

True or False: you can find retinol in plant materials.

Answer 3

False

Question 4

Where is retinol found?

Answer 4

only in animal liver and fat

Question 5

What are carotenes?

Answer 5

plant precursors of vitamin A

Question 6

Where are carotenoids found?

Answer 6

in high levels of fresh yellow, red, green, and orange plants

Question 7

What are carotenoids not found in?

Answer 7

old corn stover or old hay

Question 8

What is the most abundant carotenoid?

Answer 8

beta-carotine

Question 9

Where is beta-carotine converted into retinal?

Answer 9

in intestinal epithelial cells

Question 10

What species have no ability to convert carotenes to retinol?

Answer 10

cats, mink, and raptors

Question 11

Since cats cannot convert carotenes into retinol, what must be in their diet?

Answer 11

retinol/retinl esters

Question 12

What animal also should have retinol in their diet because they cannot convert carotenes into retinol very well?

Answer 12

pigs

Question 13

What does cooking food do to carotenes?

Answer 13

it frees up some from vegetables, but destroys others

Question 14

What are some vitamin A supplements that can be added into a diet?

Answer 14

Retinyl palmitate and retinyl acetate

Question 15

What can destroy vitamin A in feeds?

Answer 15

pelleting, extrusion, and moisture

Question 16

Retinol is a prohormone, what must it be converted into in order to be used?

Answer 16

retinoic acid (a hormone)

Question 17

During bone growth, what is vitamin A vital in?

Answer 17

the proper remodeling of bones

Question 18

How can vitamin A deficiency affect bone growth?

Answer 18

it can cause cessation of endochondral bone elongation, though periosteal bone growth is unaffected

Question 19

In respect to embryonic development and reproduction, what does vitamin A deficiency cause?

Answer 19

it causes decreased fertility, abortions, malformed fetuses, and teratology

Question 20

What is teratology?

Answer 20

testicular degeneration with poor sperm talks

Question 21

When a cow is vitamin A deficient, what are the ailments of the calves that they give birth to?

Answer 21

they have domed heads, thickened carpal joints, all of the foramina in bones are narrowed which causes blindness, and cerebrospinal fluid pressure is increased

Question 22

How does vitamin A deficiency affect epithelial cells?

Answer 22

it causes atrophy and metaplasia to cells and their secretion of mucus decreases

Question 23

What are the original epithelial cells replaced by in vitamin A deficient animals?

Answer 23

the original epithelial cells are replaced by stratified keratinized epithelium

Question 24

What is metaplasia?

Answer 24

simply a change in tissue type

Question 25

How does vitamin A deficiency affect the immune system?

Answer 25

primary and secondary lymphoid organs are reduced, antibody titers are reduces, and cell-mediated immunity is compromised

Question 26

How does vitamin A deficiency affect vision?

Answer 26

night blindness; in severe cases it causes eyes to loos pupillary light reflex

Question 27

What is keratomalacia?

Answer 27

corneal metaplasia, as vitamin a controls cell differentiation

Question 28

What is xeropthalmia?

Answer 28

dryness and thickening of the conjunctiva develops because the secreting epithelium is replaced by a keratinized epithelium in vitamin A deficient species

Question 29

Where are the highest levels of beta-carotine found in animals?

Answer 29

in the corpus luteum

Question 30

When are herbivores likely to get vitamin A deficient?

Answer 30

when they are on all hay diets or dry withered pasture by the end of winter

Question 31

When are cats likely to get vitamin A deficient?

Answer 31

if liver is withheld from their diet or no retinyl ester is added to the diet

Question 32

What is a vitamin A deficiency specifically to turtles?

Answer 32

Hypovitaminosis

Question 33

What is hypovitaminosis?

Answer 33

when the squamous metaplasia of orbital glands and ducts which

Question 34

What are symptoms of hypovitaminosis?

Answer 34

swollen eyelids, loss of weight, raw skin, abnormal eyes in embryos

Question 35

What is a vitamin A deficiency in birds?

Answer 35

caged avian vitamin A deficiency (not really a specific name but whatever)

Question 36

When do birds usually get caged avian vitamin A deficiency?

Answer 36

when they are fed seed based diets

Question 37

What are symptoms of caged avian vitamin A deficiency?

Answer 37

hyperkeratosis (white plaques) in and around the mouth, eyes, and sinuses

Question 38

What are some chronic conditions associated with vitamin A deficiency?

Answer 38

conjunctivitis, sinusitis, and bumblefoot

Question 39

What are symptoms of vitamin A toxicity?

Answer 39

anorexia, thickened skin, accelerated resorption of bone and cartilage and accelerated formation of periosteal bone, premature closer of physis of bones

Question 40

How can cats get vitamin A toxicity?

Answer 40

they are fed too much liver

Question 41

What are some symptoms that cats get when they have vitamin A toxicity?

Answer 41

excessive resorption of bone, subperiosteal bone formation, exostosis, and the fusion of joints

Question 42

What is exostosis?

Answer 42

bone forming in tendon sheaths and other places bone is not normally found

Question 43

What does vitamin A toxicity eventually lead to in cats?

Answer 43

the complete fusion of the spine

Question 44

What is a vitamin A toxicity in cattle?

Answer 44

hyena disease of cattle

Question 45

What can cause hyena disease?

Answer 45

administration of large amounts of vitamin A to young calves

Question 46

What is hyena disease?

Answer 46

the premature closure of the physes, especially those in the hind limbs

Question 47

What is the end result to a calf with hyena disease?

Answer 47

they have depressed skeletal growth characterized by hind legs that are considerable shorter than the front legs

Question 48

What liver should you not feed to an animal?

Answer 48

POLAR BEAR - it has too much vitamin A per gram