Vitamin Functions, Deficiencies, and souces

Vitamin Functions, Deficiencies, and souces

1. Vitamin A

   • Functions
     • Functions include normal maintenance of the eyes and epithelium (membrane) tissue of the respiratory, digestive, urogenital systems, and the skin.
     • Vitamin A is also needed for normal bone growth, body growth and normal tooth development
   • Sources
     • Vitamin A can be provided as a synthetic vitamin or as carotene,
     • Vitamin A itself is only present in animals, but plants contain the precursor, carotene.
     • Carotene is found in good quality, fresh, green forages in generally sufficient amounts.
     • Excellent sources of carotene are green, leafy hays that have been in storage less than one year; dehydrated, pelleted legume hays; and good quality grass or legume silage
     • Other carotene sources include yellow corn, fish liver oil, dehydrated alfalfa meal and whole milk
   • Deficiencies
     • Night blindness (inability to see in dim light) is a symptom of severe vitamin A deficiency.
       • Vitamin A is part of the visual purple of the eye, which is depleted through the action of light.
       • Visual purple is required for vision in dim light.
       • Animals suffering from night blindness will recover when sufficient amounts of vitamin A are added to the diet.
       • Animals can become permanently blind when vitamin A deficient.
     • Excessive watering of the eyes and development of cornea ulcerations are also indications of possible vitamin A deficiency
       • Other indications include nervous incoordination shown by a staggering gait, diarrhea, reduced appetite, poor growth and weight loss
       • Also, unsound teeth and rough, dry skin may be a sign of vitamin A deficiency.
       • Paralysis of some parts can occur in some species.
       • Young animals suffer from deficiency sooner because of their greater requirements and reduced storage ability
     • Reproductive problems include poor conception rates, reduced fertility in males, shortened gestation periods, and incressed retained placenta.
       • In poultry, discharges from the eyes and nostrils can occur, as well as wobbly gait in chicks, reduced egg production and hatchability of eggs

2. Vitamin D

   • Sources
     • Diets that include sun-cued forages generally provide sufficient vitamin D
     • Animals regularly exposed to sunlight or ultraviolet light will not develop deficiency symptoms
     • Green forages, barn-cured hay, and silage have some vitamin D
     • Grain, grain by-products, and protein feeds have almost no vitamin D
   • Function
     • Vitamin D is important for calcium absorption and phosphorus metabolism in the baody
     • Rickets is prevented by vitamin D, along with calcium and phosphorus
     • Vitamin D also promotes sound teeth
   • Deficiencies
     • A shortage of vitamin D will result in rickets in young or osteoporosis in adults with insufficient calcification of the bones
     • However, less vitamin D is required when a good balance of phosphorus and calcium is present
     • Symptoms of vitamin D deficiency are decreased appetite, slower growth, digestive disturbances, stiffness in gait, and sometimes the developemnt of tetany and convulsions
     • As the disease progresses, joints enlarge and become swollen and stiff
     • Pregnant animals might give birth to dead, weak or deformed young because of vitamin D deficiency
     • Chickens will show rickets, poor feathering and growth with a reduduction of egg production, hatchability and poor eggshells in laying hens

3. Vitamin E

   • Function
     • Vitamin E functions as an antioxidant, which helps in absorption and storage of vitamin A
     • As an antioxidant, it also acts in other metabolic functions in the cell
     • Vitamin E is essential for the integrity of red blood cells and in cellular respiration, primary in heart and skeletal muscle tissues.
     • It is also a regulator in the synthesis of DNA and vitamin C
   • Sources
     • Good dietary sources of vitamin E include whole cereal grains, the germ or germ oils of cereal grains, green forages, alfalfa meal, rice polishings, wheat germ meal, and good quality hay
     • After a long storage period, the vitamin e level in feeds declines
     • It is rapidly destroyed when near rancid fat
     • Vitamin E is seldom deficient in the diet unless feeds were produced on selenium-deficient soils
     • Vitamin e is produced commercially and can be added to the diet when needed by using a vitamin premix or injecting into the muscle
   • Deficiencies
     • Vitamin E deficiency looks similar to selenium deficiency-- white muscle disease or nutritional muscular dystrophy
     • Hatchability of eggs is reduced, although production does not appear to be affected
     • Extended vitamin E deficiency in poultry will cause permanent sterility in the male and reproductive failure in the female
     • The addition of selenium to the diet can prevent some symptoms of vitamin E deficiency

4. Vitamin K

   • Sources
     • Dietary sources of vitamin K include green, leafy feeds (either fresh or dry); fish meal; liver; and soybeans
     • Vitamin K usually widely available in normal farm rations, and is synthesized by all classes of farm animals
     • However, it is common to add vitamin K to swine diets and chick starter rations
   • Deficiencies
     • Vitamin deficiencies K rarely occur because it is synthesized in the rumen and in the intestinal tract of monogastric animals.
     • Feeding moldy feeds with high dicoumarol content, such as moldy sweet clover, might cause a vitamin K deficiency
     • This can lead to bleeding syndrome called sweet clover poisoning or bleeding disease
     • Moldy feeds wit high dicoumarol content fed to swine or poultry will also cause internal bleeding and death
     • Feeding vitamin K or water-soluble synthetic forms of the vitamin will counteract deficiency effects.
   • Function
     • Vitamin K is necessary for the formation of prothrombin in the blood, which helps blood clot