Vitamin A

Question 1

Vit A deficiency on bones

Answer 1

cessation of endochondral bone elongation

• -Short and think leg bones,
• -Skull bones fail to remodel properly > Raises CSF pressures (Vit A toxicity can do this too)

Question 2

Vit A Toxicity

Answer 2

1. Thick Skin
2. Congenital Malformations (Cleft Palate in puppies?)
3. Accelerated resorption of bone and cartilage – Accelerated formation of new periosteal bone (Esp in cats)
4. Premature closure of physis in bones of growin animals – Hyena Disease

Question 3

Vit A deficiency and Immunity

Answer 3

Primary and Secondary lymphoid organs are reduced in size

Reduced Ab titers
Cell mediated immunity compromised (Decrease in Th and NK cells)

Question 4

Vit A deficiency in Epithelial Lining and Infection

Answer 4

Epithelial cells that are normally columnar, cuboidal, or tranistional undergo atrophy and METAPLASIA –> Secretion of mucus decreases

Original epithelial cells are replaced by stratified keratinized epithelium

Increased incidence of Respiratory Infections

Question 5

Vit A Toxicity Cattle

Answer 5

Hyena Disease

1. Premature closure of the physes

Question 6

Vit A Toxicity Cats

Answer 6

High amounts of liver

1. Excessive resorption of bone
2. Subperiosteal bone formation
3. Exostosis = Bone forming in tendon sheaths and other places bone is not normally found
4. Arthrodesis (Fusing) of joints

Question 7

Vit A deficiency in Embryonic development and Reproduction

Answer 7

Decreased fertility, abortions, malformed fetuses = teratology, testicular degeneration with poor sperm counts

Cows give birth to calves with narrow foramina -> Blindness

Question 8

Vit A deficiency and Vision

Answer 8

1. Night blindness
2. Lose pupillary light reflex (SEVERE) (Optic nerve damage too?)
3. Keratomalacia = Corneal metaplasia
4. Xeropthalmia = Metaplasia of tear gland epithelium

Question 9

Caged Avian Vit A Deficiency

Answer 9

Seed Based Diets

White plaqued (hyperkeratosis) in and around the mouth, eyes, and sinuses
-->Chronic = Conjuctivitis, sinusitis, and bumblefoot

Question 10

Vit A precursor to Hormones

Answer 10

Precursor to a group of hormones (retinoic acids) which affect gene expression and cell differentiation

Question 11

Vit A deficiency in Turtles

Answer 11

Hypovitaminosis A

Squamous metaplasia of orbital glands and ducts -> Swollen eyelids, Loss of weight, Raw skin, Abnormal eyes in embryo

Question 12

Animals with no ability to convert Carotenes to Retinol

Answer 12

Cats, Minks, and Raptors

Pigs can’t convert B-carotene to retinol well