Vitamins – Function & Deficiency

Vitamins are nutrients that animals require in very small quantities for normal growth and maintenance of life, and the requirements for each differ considerably. Vitamins are involved in metabolic processes as co-factors in energy, protein and fat utilisation as antioxidants, assisting in the uptake of minerals and their balance, and are associated with the production of hormones and many other vital body functions.

Pastures contain a wide range of vitamin precursors and vitamins and to supplement dietary intake the animal can synthesise many vitamins within the body. Vitamin D is produced in the skin by sunlight, vitamin K and B-group vitamins are produced by bacterial fermentation in the gut and vitamin C is produced in the liver. Vitamin A and E are not synthesised within the animal body and is exclusively obtained from the diet. At least 14 vitamins have been accepted as essential food factors and have been divided into two main groups: fat-soluble and water-soluble.

Vitamin – Fat Soluble

Role

Essential for growth processes. Required for visual pigments in eyes, tendon strength, bone remodelling, health of skin (epithelial tissues) and mucous membranes.
Vitamin A is important in the resistance to disease and promotion of healing through its effect on the immune system and epithelial integrity.

Common Deficiency Effects

Progressively poor night vision, blindness, loss of appetite, poor growth, poor reproductive performance, epithelial infections, keratinisation of the skin and cornea and susceptibility to infection.

Role

Regulates Calcium and Phosphorus uptake, maintains optimum balance and controls secretion.
Regulates the expression of genes and the activity of cells associated with the immune system.

Common Deficiency Effects

Rickets and osteomalacia, calcium uptake is depressed with a Vitamin D deficiency, leading to lameness, weak bones, swollen joints, loss of appetite.

Role

Acts as a biological antioxidant in association with selenium to protect cells against oxidative damage caused by free radicals.

Common Deficiency Effects

Muscle degeneration (myopathy), white muscle disease, lameness, tying up, cardiac disease, liver damage, rough coat and subcutaneous swellings.

Role

Essential for activation of blood clotting factors (prothrombin synthesis) in conjunction with calcium, as well as other proteins in the body.

Common Deficiency Effects

Deficiency is uncommon as it is generally considered that under ‘normal’ conditions bacterial synthesis in the digestive tract supplies sufficient vitamin for the animal’s needs. If deficiency was to occur it would result in anaemia and delayed clotting, leading to haemorrhage.

Vitamin – Water Soluble

Role

Carbohydrate and fat metabolism, nerve transmission.
Thamin triphosphate is involved in the activation of the chloride ion channel in the membranes of nerves.

Common Deficiency Effects

Poor growth, loss of appetite, emaciation, abnormal heartbeat, muscle tremors, incoordination, stiffness in limb, progressive dysfunction of the nervous system and lung fluid build-up and polyneuritis (any disorder that affects the peripheral nerves collectively).

Role

Carbohydrate and amino acid metabolism. Involved in the metabolic function with two coenzymes used in aerobic energy production.

Common Deficiency Effects

Poor appetite, poor growth, skin eruptions, eye abnormalities, dull dry coat and flaky skin loss, diarrhoea, hindgut inflammation in horses, and curled toe paralysis in chickens.

Role

Nicotinamide functions in the animal body as the active group of two important coenzymes. Nicotinamide in the tissues is involved in the metabolism of carbohydrates, fats and amino acids to energy. (Higher requirement in exercising horses)

Common Deficiency Effects

Poor growth, anorexia, enteritis, dermatitis, diarrhoea, vomiting and mouth ulcers.
Bone disorders, feathering abnormalities and inflammation of the mouth and upper part of the oesophagus are deficiency signs in fowl.

Role

A constituent of many coenzymes involved in metabolism of carbohydrates, proteins and fats to energy. A constituent of coenzyme A, which is important for fatty acid oxidation, acetate metabolism, plus cholesterol and steroid synthesis.

Common Deficiency Effects

Poor growth, dermatitis, gut ulcers, diarrhoea, scaly skin, ‘goose-stepping in pigs’.
In chicks, retarded growth and dermatitis occurs, and mature birds have reduced hatchability.

Role

Vitamin B6 is involved in amino acid metabolism, this vitamin is believed to play a role in the absorption of amino acids from the small intestine. Requiring both niacin and riboflavin for energy production and blood formation.

Common Deficiency Effects

Poor growth and convulsions.
Pigs have been known to reduce their food intake and may develop anaemia.
In adult birds’ hatchability and egg production are adversely affected.

Role

Required in much smaller amounts than other vitamins. Involved in methionine synthesis, folic acid activity and propionic acid to energy.

Common Deficiency Effects

Poor growth, anaemia, poor coat/feathering.
A deficiency in young growing animals, results in growth being severely retarded and mortality is high.
Parasitised horses have responded to supplementation, presumably as a result of impaired digestive activity.

Role

Associated with B12. Involved in blood cell production. Metabolism of single carbon compounds. It is involved in the synthesis of RNA, DNA and neurotransmitters.

Common Deficiency Effects

Poor growth, anaemia, poor hatchability in fowl.

Role

Carbon dioxide transfer, involved in coenzyme activity during synthesis of glucose and formation of fats, RNA and DNA in cells.

Common Deficiency Effects

Foot lesions, hair loss, Fatty Liver and Kidney Syndrome (FLKS).
Responses of biotin supplementation has reported to improve hoof structure and strength.

Role

Important antioxidant action by removing excess oxygen to protect fats and proteins in cell membranes, it enhances bone and collagen formation and utilisation of some amino acids.
Aids utilisation of iron and folic acid uptake.

Common Deficiency Effects

Reduced resistance to infection.
In human’s scurvy is a result of vitamin C deficiency that is characterised by oedema, emaciation and diarrhoea.

Role

A precursor of acetylcholine, a neurotransmitter vital to nerve and muscle function. A component of lecithin which play a vital role in cellular structure and activity and is critical to normal liver metabolism

Common Deficiency Effects

Poor growth, fatty liver, perosis (a disorder of poultry that is characterised by leg deformity)

By Shannon Godwin (BAppSc GDTL)

Frape, D. (2008). Equine Nutrition and Feeding. John Wiley & Sons.

Hungerford, T. (1990). Diseases of Livestock (Vol. 9th Edition). Roseville, NSW, Australia: McGraw-Hill Book Company Australia Pty Ltd.

Kohnke, J. (1999). Feeding Horses in Australia: A Guide for Horse Owners and Managers. Barton ACT: Rural Industries Research and Development Corporation.

McDonald, P. E. (2011). Animal Nutrition (Vol. Seventh Edition). Essex: Pearson Education Limited.