Vitamins
Vitamin A
Role of Vitamin A
• Synthesis of glycoprotein to maintain integrity of epithelial cells.
• In bone formation synthesis of mucopolysaccharides.
• Synthesis of the visual pigment Rhodopsin.
• Retinol and retinoic acid (RA) are essential for embryonic development during fetal development.
Clinical signs
• Inadequate retinol available to the retina results in impaired dark adaptation, known as “night blindness.”
• Mild vitamin A deficiency may result in changes in the conjunctiva (corner of the eye) called Bitot’s spots.
• Severe or prolonged vitamin A deficiency causes a condition called xeropthalmia (dry eye) characterized by changes in the cells of the cornea that ultimately result in corneal opacity, keratinization of the cornea, corneal ulcers, scarring, and blindness.
• Sometimes vitamin A deficiency can lead to obstruction of lacrimal ducts due to degenerated epithelial cells leading to decreased output of tears.
• Vitamin A is needed for bone formation. If vitamin A is deficient optic foramen is not formed properly. Small size optic foramen leads to the constriction of optic nerve. Permanent damage to the nerve can lead to permanent blindness.
• Infection of gastrointestinal tract, respiratory tract, uro genital tract and skin is common in Vitamin A deficiency. Deficiency of vitamin A can lead to infertility or sterility in male.
• Deficiency of vitamin A can lead to vaginitis, abnormal estrous cycle, early embryonic mortality, abortion and defective formation of foetus in females.
• Deficiency of vitamin A can lead to developmental bone deformities.
• Vitamin A deficiency leads to elevated cerebro spinal fluid (CSF) pressure results in thickened duramater leading to under absorption of CSF.
Excess- Clinical signs
Over consumption of preformed vitamin A is called hypervitaminosis A. Symptoms include nausea, headache, fatigue, loss of appetite, dizziness, and dry skin.
Supplementation
• Oils from livers of certain fish (Cod and Halibut),
• Egg yolk and milk fat.
Vitamin D
Clinical signs- Deficiency-Rickets
• Calcium and Phosphorus deposition in bones is affected and the bones are weak, more prone to fractures and deformities.
• The conditions commonly seen are bowing of legs, swollen knees and hock and arching of back. Occasionally there is paralysis.
Deficiency – Osteomalacia
• Resorption calcium and phosphorus from the bone that was already laid down.
• Bones become weak, more prone to fractures and deformities.
• It can occur in pregnant and lactating animals, which require increased amount of calcium and phosphorus
Toxicity – Clinical signs
Vitamin D toxicity (hypervitaminosis D) induces abnormally high serum calcium levels (hypercalcemia), which could result in bone loss, kidney stones and Calcification of organs like the heart and kidneys if untreated over a long period of time.
Supplementation
• Cod liver oils (rich source),
• Egg yolk and sun dried roughage’s/grains.
Vitamin E
Role of Vitamin E
• Vitamin E functions in the animal mainly as biological antioxidant.
• In association with the selenium-containing enzyme glutathione peroxidase, it protects cells against oxidative damage caused by free radicals.
Clinical signs -Deficiency
• The most frequent and the most important manifestation of Selenium deficiency in farm animals is muscle degeneration (myopathy).
• Nutritional myopathy, also known as muscular dystrophy, frequently occurs in cattle, particularly calves.
• The myopathy primarily affects the skeletal muscles and the affected animals have weak leg muscles, a condition manifested by difficulty in standing and, after standing, a trembling and staggering gait.
• The animals are unable to rise and weakness of the neck muscles prevents them from raising their heads popularly known as white muscle disease.
Supplementation
• Green fodder
• Cereal
• Grain
• Fats
• Nuts
• Oil seeds
• Legumes
Vitamin K
Role of Vitamin K
Vitamin K is required for synthesis of prothrombin in the liver, which is necessary for blood clotting.
Deficiency – sweet clover disease
• Low Prothrombin level in blood leads to hemorrhagic conditions.
• In cattle sweet clover disease is associated with Vitamin K.
• Sweet clover contains a compound dicoumarol, which lowers prothrombin content of blood.
Supplementation
• Green leafy vegetables,
• Synthesized by bacteria in gastro intestinal tract.
Vitamin C
Role of Vitamin C
• Plays an important role in the oxidative reduction reaction of living cells
• Formation of collagen and intercellular cement substance (Capillaries, teeth, bone).
• Involves in metabolism of tyrosine.
• Absorption of iron and incorporation of plasma iron into ferritin.
• Hydroxylation of deoxycorticosterone, tryptophan, phenylalanine.
Clinical signs-Deficiency
• Scurvy in adults characterized by Weakness, bleeding, loosens teeth, swollen joints hemorrhages.
• Infantile scurvy characterized by anorexia, listlessness, leg drawn up to abdomen swelling at ends of long bone, gums swollen, dyspnea, cyanosis, convulsions and death if not treated.
• Delay in wound healing.
Supplementation
• Stress increases the requirement of this vitamin.
• Citrus fruits and green leafy vegetables Formation of collagen and intercellular cement substance (Capillaries, teeth, bone).