Vit A deficiency on bones
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)
Vit A Toxicity
- Thick Skin
- Congenital Malformations (Cleft Palate in puppies?)
- Accelerated resorption of bone and cartilage – Accelerated formation of new periosteal bone (Esp in cats)
- Premature closure of physis in bones of growin animals – Hyena Disease
Vit A deficiency and Immunity
Primary and Secondary lymphoid organs are reduced in size
Reduced Ab titers
Cell mediated immunity compromised (Decrease in Th and NK cells)
Vit A deficiency in Epithelial Lining and Infection
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
Vit A Toxicity Cattle
Hyena Disease
1. Premature closure of the physes
Vit A Toxicity Cats
High amounts of liver
- Excessive resorption of bone
- Subperiosteal bone formation
- Exostosis = Bone forming in tendon sheaths and other places bone is not normally found
- Arthrodesis (Fusing) of joints
Vit A deficiency in Embryonic development and Reproduction
Decreased fertility, abortions, malformed fetuses = teratology, testicular degeneration with poor sperm counts
Cows give birth to calves with narrow foramina -> Blindness
Vit A deficiency and Vision
- Night blindness
- Lose pupillary light reflex (SEVERE) (Optic nerve damage too?)
- Keratomalacia = Corneal metaplasia
- Xeropthalmia = Metaplasia of tear gland epithelium
Caged Avian Vit A Deficiency
Seed Based Diets
White plaqued (hyperkeratosis) in and around the mouth, eyes, and sinuses -->Chronic = Conjuctivitis, sinusitis, and bumblefoot
Vit A precursor to Hormones
Precursor to a group of hormones (retinoic acids) which affect gene expression and cell differentiation
Vit A deficiency in Turtles
Hypovitaminosis A
Squamous metaplasia of orbital glands and ducts -> Swollen eyelids, Loss of weight, Raw skin, Abnormal eyes in embryo
Animals with no ability to convert Carotenes to Retinol
Cats, Minks, and Raptors
Pigs can’t convert B-carotene to retinol well
