Vits - Not Bs

Vitamin C

Ascorbic acid

Ascorbic acid sources

-citrus fruits

- green, leafy vegetables

- synthetic

Only essential in diet of primates, guinea pigs and fruit bats. other species synthesis it from glucose

Ascorbic acid metabolic functions

-normall collagen formation

- metabolic oxidation + reduction pathways

- Iron transport

- Antioxidant

Ascorbic acid deficiency signs

Scurvy

- muscle joint pain

- red dots on skin

- bleeding and swelling of gums

- diarrhoea

- rough hair coat

- reduced immune function

Vitamin E

a-Trocopherol

Sources

- Green fodder (grass, green vegetables)

- Cereals

Little body reserves so dietary intake is important

Metabolic Functions

-biological antioxidant

- acts in combination with selenium containing enzyme, Glutathione Peroxidase, to protect cells from oxidative damage caused by free radicals

- Important for normal reproductive function, muscular function and capillary integrity

Problems associated with vitamin E deficiency

- Nutritional myopathy: white muscle disease (calves), Stiff lamb diseases

- Cardiac disease: Mulberry heart disease (pigs, Calves)

- Brain damage: crazy chick disease

- Lameness and Muscle stiffness: Tying-up (horses)

"Tying up" in horses

Muscle cramps, usually affecting the largest muscles (back and hind quarters).

Very painful, causes distress and anxiety, increases respiratory rate sweat or even cause them to display coli like symptoms.

Vitamin D

Calciferol

Two most important forms

D2: Ergocalciferol - derived from ergosterol

D3: Cholecalciferol - derived from 7-dehydrocholesterol

Sources of calciferols

-sunlight on skin

- oily fish

- egg yolk

- hay

- colostrum

Metabolic functions:

- Promotes Ca2+ absorption from digest in gut lumen

- enhances intestinal absorption of Ca when blood Ca2+ concentration decreases

- stimulates phosphorous uptake from gut and reabsorption of Ca2+ and P from bone and kidney

Problems associated with Vitamin D defficency

- Rickets: soft, weak, deformed bones in young growing animals

- Osteomalacia in adults: weak bones

-Poor egg shell quality and weak bones in poultry

Vitamin K

Quinones

Examples of different forms

Phylloquinone

Menaquinone

Sources

- green leafy materials

- egg yolk

-liver

-fish

-gut bacteria synthase

What destroys Vitamin K?

Heat and exposure to sunlight

Metabolic functions

- Essential for normal clotting of blood

- Bone and Kidney function

Signs of deficiency

-Chicks: anaemia and delayed clotting of blood

- unlikely to occur in cattle, horses or pigs

-microbial population of ruminants can synthesise

Vitamin A

Retinol

Metabolic functions of retinol

1. Formation and integrity of epithelia and mucous membranes

2. Retinal function (combines with opsin to form rhodopsin- needed for night vision)

3. Bone Growth

4. Immune function

Provitamin A

beta-carotene

converted to retinol during absorbing through gut wall

What does the availability of beta-carotene vary with?

1. Age - young animals are poor converters, obtain pre-formed retinol from milk.

2. Species - Cats cannot convert beta-carotene

3. Breed - channel island cattle are very poor converters

4. Health - diseases affecting gut wall and liver function

Where is retinol stored?

liver

Sources of Retinol

cod liver oil, egg yolk, milk fat

Sources of Beta-Carotene

Fruits and vegetables that are red, orange, yellow, and deep green (also grass)

Retinol deficient foods

Cereal grains, meat

Retinol Deficiency in Cattle

Mild: rough, scaly skin

Prolonged: 'Night blindness', lachrymation, corneal opacity. Infertility, abortion, retained placenta, still-birth

Deficiency rare in adults carotenoids acquired in pasture create enough hepatic stores of retinol to last over winter.

More common in intensely reared indoor beef cattle on cereal diets

Retinol Deficiency in Dogs and Cats

Occur when fed all meat diets with no liver.

Dogs: rough, scaly skin, night-blindness, abnormal skeletal growth

Cats: foetal defects and can result in complete infertility

Retinol Deficiency in Poultry

Pale comb and wattles, loss of condition, retarded growth, ruffled plumage

More susceptible to infectious diseases

High mortality rate

Poultry require vitamin A supplements in feed.

Hypervitaminosis A in Dogs + Cats

- abnormal bone deposition

- lameness

- vertebral spondylosis

-gingivitis

- weight loss

- poor coat

Hypervitaminosis A in Pigs

excessive intake by pregnant sows may cause cardiac abnormalities in piglets