Chapter 8 (pt.2): Vitamins (Hill) Flashcards
in what way do vitamins A and D act like hormones?
regulating DNA transcription
Vitamin A and E - required by what animals and have what effects on the body?
required by all animals
may have beneficial effects on immunity
deficiency of fat soluble vitamins accompany what condition?
fat malabsorption
Source of Vitamin A and carotenoids
plants do not contain vitamin A (retinol) but they do contain carotenoids which can be split in the body to form retinol except in cats and they therefore must be given retinol in the diet.
hay and corn - contain carotene
cod liver oil - retinol
function of Vitamin A (retinol) and carotenoids
- light pigment rhodopsin aka night vision
- affects DNA transcription by:
- promoting skin and mucosal differentiation and proliferation. carotenoids have been used at high doses to treat solar dermatitis and squamous cell carcinoma in dogs
- increased immunity
- carotenoids act as antioxidants
Vitamin A (retinol) and carotenoids: deficiency
- night blindness
- **common in seed-eating birds: cutaneous abscesses
- poor heat tolerance, emaciation, weakness, mastitis, etc
Vitamin A (retinol) and carotenoid: toxicity
- cervical spondylosis in cats fed exclusively liver*
- and in anteater pet foods*
- polar bear liver contains very high concentrations*
Vitamin D sources
- dogs and cats cannot synthesize in skin so must have external sources*
- formed in skin by action of sunlight
- hays, fish liver oils, irradiated yeast
what species of animal cannot use Vitamin D2 and must use Vitamin D3? ***
***new world monkeys and poultry - must Vitamin D3 only!
Vitamin D function
hormone which regulates Ca and P absorption from intestine and resorption from bone and Ca absorption in kidney
Vitamin D deficiency
- **Rickets seen in animals deprived of sunlight - especially reptiles
- chronic renal failure
Vitamin D toxicity
excess supplementation in pet foods or owners
rodenticide poisoning
Vitamin E sources
vegetable oils, wheat germ
Vitamin E function
Vitamin E (tocopherol) acts as an antioxiant in pet food but is oxidized over time. tocopherol acetate in pet food is converted to Vitamin E in the body where its used as an antioxidant but has no oxidant activity in food before transformation.
- immune stimulant
Vitamin E deficiency
- myopathy, poor reproduction, mastitis
- common in fish-eating mammals**
- ** possibly responsible for steatitis in cats
Vitamin E toxicity
high doses interfere with Vitamin K metabolism and platelet function
therapeutic uses of Vitamin E
is used for any disease where oxidation is part of pathogenesis like reperfusion injury
Vitamin K sources
intestinal bacteria
green plants
Vitamin K function
cofactor in synthesis of clotting factors: 2, 7, 9 and 10
Vitamin K deficiency
symptom is hemmorhage as in Warfarin poisoning
also seen in fat malabsorptoin due to bile duct obstruction and fatty liver disease
what water soluble vitamin is produced in the rumen not an essential nutrient in cattle?
vitamin B
what water soluble vitamin is easily destroyed by heat so “overage” is added to pet food diets to accomodate losses?
vitamin B
Vitamin C sources***
** synthesized by most species except primates, guinea pigs, some bats, some birds (Bulbuls), fish and invertebrates **
Vitamin C function
antioxidant
hydroxylation of proline and lysine in collagen formation*
fibroblast and osteoblast function
important for immunity and carnitine synthesis
Vitamin C deficiency
- “scurvy” - loose teeth, poor wound healing, ruptured capillaries, etc.
- dogs and cats synthesize ascorbic acid in liver
- some say supplementation is needed during times of stress