Vitamins are complex organic compounds essential in small quantities for normal growth, maintenance and reprodution of animal life.
Animals are unable to synthesise many of these compounds and they must obtain them “ready-made” directly or indirectly from the diet.
Until the turn of the twentieth century, nutritionists and lay people alike considered carbohydrates, fats, protein plus certain minerals to be the only dietary elements required for the normal functioning of the animal body. After animals became ill on a diet solely of the above nutrients supplemented with mineral elements, however, it became evident that natural foods must contain other substances in the diet indispensable for health, and a deficiency of one or more of these substances in the diet would result in a breakdown of bodily activities and produce symptoms of disease. This substances were first called “accessory food factors”, later to be re-named “vitamine” (vitamins) by C. Funk of Poland.
Since their discovery, researchers have been able to isolate, purify, synthesise and elucidate the physiological action of many of these compounds. By 1913 only two vitamins had been discovered; one was fat soluble and the other was water soluble, so it was proposed to name them “fat-soluble A” and “water-soluble B”. Classification by solubility in water or fat is still in use.
Nearly all normal. mixed diets will include sufficient amounts of vitamins and an avitaminosis (complete lack of one vitamin) is only likely to occur when a diet consists of only one kind of food.
Each vitamin influences a number of vital processes in the body and even a shortage eventually leads to irregularities in the metabolism and the functions of some tissues. Such a deficiency disease is called a hypovitaminosis and reveals itself in such symptoms as excessive fatigue and weakness, growth, retardation, reduced resistance to diseases, disturbances in reproduction and low resistance to parasites.
If there is a shortage of only one vitamin in a diet the hypovitaminosis due to this vitamin is usually recognisable by the symptoms and provided there is no irreversible damage, which, unfortunately, is often the case in a vitamin D deficiency, the disease can be cured by administering the appropriate vitamin supplement. Should a diet be insufficient in more than one vitamin, however, it is very difficult to diagnose a hypovitaminosis, as the symptoms are generally many and varied.
Frequently a pet owner does not always recognise or recognise in time that a diet is deficient in a vitamin, as the animal’s organism may still hold reserves of this vitamin so that the symptoms of the deficiency disease are delayed or only slight at first.
Factors leading to a vitamin deficiency:
a) Inadequate dietary supply of vitamins,
b) Increased vitamin requirements at times of intensive growth, during breeding, pregnancy and when rearing young as well as all stress situations such as shows, transport and change of envíronment,
c) Increased vitamin requirement due to reduced availability caused by intestinal disease,
d) Damage to organs serving a vitamin storage depots, e.g., liver cirrhosis,
e) Reduced vitamin availability during treatment with antibiotics, sulpha drugs and chemotherapeutics.
As already mentioned, if the hypovitaminosis has not resulted in any irreparable damage to an animal’s health, it can generally be cured quickly by the administration of a good vitamin supplement.
A hypervitaminosis, which is a disease resulting from an overdose of a vitamin, is even easier and faster to remedy. A hypervitaminosis is really only possible through the vitamins A and D and then only when the animal has ingested excessive amounts of one of these vitamins through an unbalanced and incorrect diet. It takes a hundred to a thousand times the recommended daily dose to produce a hypervitaminosis.
As scientists established the proper relationship between the nutrients of which food is composed, they discovered that a scant but well-balanced diet is infinitely superior to a lavish but unbalanced one. This is particularly true of the vitamins. Not only must the correct amount of each vitamin be present in the diet, but they must also be in the correct relationship to one another. A shortage of one vitamin cannot be compensated by increased amounts of the others. The vitamins are interrelated and the biosynthesis of vitamin C requires biotin, for example, or a vitamin B6 deficiency reduces the absorption of vitamin B12 in the gut as another.
A good vitamin supplement must therefore contain the right vitamins for its purpose and in the correct amounts and proper relationship. Years of research and experiments on their own animals have enable NEKTON to produce this excellent range of well-balanced pet diets and vitamin and mineral supplements. In addition NEKTON use only the very best forms of vitamins in their products. Special processing methods produce the pure vitamins in water-soluble powder form, meaning the products are easy to administer because of their water solubility and the vitamins remain active longer and better.
We will now describe each vitamin in detail.
Vitamin A does not occur as such in plant tissues but rather as its precursor, carotene. Carotene, or provitamin A, which occurs in yellow fruits, carrots and particularly in turnip, dandelion and beet greens, can be converted by the body into the active vitamin. The vitamin itself is found only in animal tissues in which the provitamin forms have already been metabolised into the vitamin. Liver, the organ in which vitamin A is stored, is the richest source of vitamin A and at one time the liver oils of cod, spermwhale and halibut were administered in order to avoid a deficiency. As vitamin A has a very labile reaction to oxidation, however, and these oils tend to oxidize easily and therefore put the animal’s metabolism under extreme strain, they are hardly used today.
Vitamin A is also known as the anti-infective vitamin as it protects the tissues of the epithelial cells of the respiratory, alimentary and genito-urinary tracts enabling them to maintain their ability to secrete mucus and thus their resistance to infection.
One of vitamin A’s most important physiological functions is the maintenance of the visual sense organs. Insufficient vitamin A in the diet interferes with the regeneration of visual purple in the eye, causing night blindness, and leads to degenerative changes in the eye epithelium – the eye “dries out”.
Vitamin A is stored in the liver but the liver of young animals is less able to store it that the adults’ can. A vitamin A deficiency in the diet, therefore, leads to illness and disease in the young faster than in adult animals. Specific vitamin A deficiency symptoms in young animals are retarded growth and low resistance to infective organisms. Due to the loss of the epithelial cells’ ability to secrete mucus the respiratory and alimentary tracts are usually affected first, resulting in pneumonia and diarrhoea. A classic vitamin-A-deficiency is choanal in amazons (oral area will show thickening and may shut due to swelling).
Provitamin A (Beta-Carotene)
Carotene is a precursor of vitamin A and can be converted into the active vitamin by the body.
The provitamin beta-carotene is found in the green parts of plants in a concentration of 10-200 mg/kilo and carrots have a particularly high concentration of this substance.
Carotenoids originate exclusively in plant material. The oxidisation of carotenoids produces xanthophyll and zeaxanthin, which are frequently used as natural colourings, e.g., when feeding laying hens to give the egg yolk a better yellow colour or to enhance the plumage of cage birds.
Carotenoids are found everywhere in nature and produce the yellow to red shades in plants and animals. They occur in blossoms, greens, corn, tomatoes, carrots, oranges, in the plumage of such birds as flamingos, and in fish and crustaceans.
Today carotenoids can be produced synthetically and are identical to the natural substances. An animal’s organism processes and absorbs them in exactly the same way, whether the source is natural or synthetic.
Vitamin D (D2 Ergocalciferol, D3 Cholecalciferol)
Vitamin D is also known as Calciferol. This name arose from its ability to enhance the absorption of calcium. Only two forms, ergocalciferol and cholecalciferol, are important as dietary sources of the vitamin. Like vitamin A, vitamin D3 occurs naturally only in animal tissues, particularly in salt-water fish such as tuna, halibut and cod liver. The amount of vitamin D2 found in plant foods is very slight and depends upon the degree of exposure of the plant material to ultraviolet light (sunlight) following harvesting.
Vitamin D’s most important function is in regulating the calcium and phosphorus metabolism. Vitamin D2 and vitamin D3 are almost equally valuable in their antirachitic effect on mammals, whereas chicks and poults can efficiently utilise only vitamin D3. As vitamin D3 can also be stored better in the liver, NEKTON use only vitamin D3 in the manufacture of their products.
Vitamin D is required for the normal calcification of the growing bone and promotes the calcification of the eggshells of birds as well as maintaining blood plasma calcium and phosphorus levels and aiding calcium absorbtion from the intestine.
Many factors, the length of time an animal spends in the sunshine; its living habits and intake of calcium and phosphorus, all affect its dietary requirements.
Over a long period of time a deficiency of vitamin D in the young will lead to retarded growth and rickets, and to osteomalacia (lack of mineralised bone) in the adult animal, especially during reproduction and lactation.
Vitamin E (Tocopherol)
Vitamin E occurs in multiple forms, the alpha-tocopherol being much more active than the others and the most easily absorbed. Alpha-tocopherol is the sole tocopherol in the green parts of plants and is found together with the others in the seeds of plants and particularly in the oils extracted from these seeds. As it is the most potent form of the tocopherols in the plant kingdom, NEKTON use this form of vitamin E in all their products.
Vitamin E plays a vital role in all the body cells and in the fertility of most animal species. It also protects the vitamins A and C, vitamin A being conserved by vitamin E in chicks, for example, and its absorption or utilisation aided, meaning birds require a somewhat greater supply of vitamin E than mammals.
Vitamin E maintains normal muscle metabolism and ensures good functioning of the central nervous system and vascular system.
A vitamin E deficiency can lead to myocardial degeneration and degenerative changes in the skeletal tissues, reproductive tissues, liver and red blood cell membranes. Animals suffering from a deficiency of this substance are generally susceptible to infectious diseases. It is very important to ensure an adequate supply of vitamin E at all times, as any damage to organs due to a deficiency is usually irreversible.
Vitamin K (K1 Phylloquinone, K2 Menaquinone, K3 Menadione)
Vitamin K is essential for regulating the plasma content of proteins required for blood coagulation.
Alfalfa is an especially rich source of vitamin K1, which also occurs in lesser quantities in dark, leafy vegetables. K2 results as a synthesis by micro-organisms, particularly by bacteria living in the intestinal tract. The synthetic compound menadione (methyl-naphthoquinone), soluble in water, is even more active than vitamin K1.
These three forms, all possessing almost the same biological effect, are converted into active vitamin K by the body.
Vitamin K controls the synthesis in the liver of prothrombin and other blood-clotting factors to such an extent that a vitamn K deficiency reduces blood coagulation and leads to heavy haemorrhaging, especially in birds. This is the reason vitamin K is also given the name antihaemorrhagic vitamin or coagulation vitamin. Treatment with antibiotics and sulpha drugs are factors affecting the availability of vitamin K, as both prevent the correct synthesis of this vitamin by the intestinal flora. Birds have such a short intestinal tract and so few micro-organisms that they require a dietary source of vitamin K. This supply should be increased when they are receiving medical treatment as above or when breeding, as the vitamin K storage in the liver of newly hatched chicks is very small if not enough has been secreted into the eggs.
Vitamin C (Ascorbic acid)
Scurvy was a disease of sailors in the days of sail and was cured or avoided by including citrus fruits, i.e., fruit rich in vitamin C, in the diet, which led to this vitamin being called the anti-scurvy vitamin by some people. A high percentage of vitamin C is to be found in all greens as well as in many fruits and fresh vegetables, but animal tissue can only store this vitamin in minute quantities. Vitamin C helps form and maintain the “cementing” materials that hold body cells together and strengthen the walls of blood vessels, and it aids in healing wounds. Ascorbic acid participates in the synthesis of certain hormones and in cellular respiration.
Except for the primates (including Man), guinea pigs and deer, almost all animals are capable of forming vitamin C themselves from glucose. Today nearly all standard mixed diets will include adequate amounts of vitamin C so that deficiency diseases due to a lack of this vitamin seldom arise. An extra supply, however, will always be beneficial to an animal, and any surplus vitamin C is passed out of the body with the urine. As the body utilises larger-than-normal amounts of vitamin C in such stress situations as during illness, transport, etc., and the liver (in mammals) and the kidneys (in birds) cannot store more than very limited quantities of this vitamin, no balanced vitamin supplement should be without it.
The Vitamin B Complex
The B group of vitamins is made up of a number of water-soluble compounds differing greatly in their structures. Eight of them are of essential importance to an animal’s metabolism.
Treatment with antibiotics and sulphonamides can destroy or reduce the availability of the B complex, which means that an animal’s diet should be generously supplemented with these vitamins at such times to ensure maintenance of the bodily activities.
Most members of the group are poorly stored and very often destroyed by cooking. In addition, absorption from the intestinal tract is generally insufficient for a captive or domesticated animal’s need, except in sheep, cattle and some in horses, meaning the food for such animals should be supplemented with the B vitamins to prevent a hypovitaminosis.
Vitamin B1 (Thiamine)
In 1898 Dr Christian Eijkman in Java saw chickens limping, reeling and generally imitating the unsteady walk of beriberi victims. He conducted experiments and found a diet of unpolished rice made the symptoms disappear. Unpolished rice, therefore, but also parboiled rice that “fixes” much of the thiamine into the grain, yeast and wheat germ are rich in vitamin B1, but an adequate supply of this vitamin can be found in most animal and plant foods.
Vitamin B1, is also known as the antineuritic factor because of its physiological function in nerve activity.
A good digestive system and the carbohydrate metabolism depend greatly on sufficient vitamin B1. That means the richer the food is in carbohydrates the higher the vitamin B1 content in the diet must be.
General deficiency symptoms are fatigue, weakness and anorexia, resulting in weight loss and retarded growth as well as neurological disturbances and circulatory and cardiac involvement.
The supply of vitamin B1 should be increased in situations requiring a faster metabolism such as pregnancy, brooding or illness. In the case of gastro-intestinal diseases, which are often a factor affecting the availability of thiamine as they reduce absorption by the intestinal wall, the diet should also be enriched.
Vitamin B2 (Riboflavin)
Vitamin B2 plays a central role in the release of energy from food. It helps in maintaining normal appetite, good digestion, healthy skin and good nerve functioning. Milk, eggs, green vegetables and yeast are rich in this vitamin.
Riboflavin is absorbed from the small intestine. A lack of vitamin B2 results in a number of different symptoms making it very difficult to diagnose. A distinct sign of a vitamin B2 deficiency in birds is severely turned-inward toes, commonly referred to as curled toe paralysis. Further symptoms are digestive disturbances, wasting, retarded growth, diarrhoea, poor hatchability and poor egg production, formation of crusty, horn-like material in the bill and small, weak babies.
Breeding birds should always have a good supply of vitamin B2 as a low riboflavin content in the eggs can mean death for the embryos and will certainly result in small babies susceptible to disease and of slow growth.
Vitamin B6 (Pyridoxine)
Pyridoxine is the collective name for the various pyridine derivatives, all of which are effective as vitamins. Vitamin B6 also exists in the form of an aldehyde (pyridoxal) and an amine (pyridoxamine). Vitamin B6 is found mainly in plants as pyridoxine and as pyridoxal and pyridoxamine in animal tissues.
Vitamin B6 helps build proteins and is essential to carbohydrate metabolism. It is needed for the biosynthesis of unsaturated fatty acids, and a deficiency can result in a loss of weight. The numerous symptoms which a vitamin B6 deficiency can produce, such as a standstill in growth, over-excitability, muscle contractions, neurological disorders of the head and neck muscles, as well as those mentioned above show how essential this vitamin is for the normal bodily activities.
As vitamin B6 in the pyridoxine form is more effective biologically for birds than pyridoxamine or pyridoxal, this form is used in all NEKTON products.
Vitamin B12 (Cyanocobalamin)
A peculiarity of vitamin B12 is that it is not formed in vegetable cells containing chlorophyll but synthesised exclusively by different micro-organisms, which are to be found in great quantities in the large intestine of herbivores for example.
Vitamin B12 has a decisive influence on all the metabolic processes and as it helps build proteins, too, diets poor in protein or fatty diets can still give full nutritive value if a vitamin supplement containing this vitamin is added. Vitamin B12 is used to treat pernicious and other forms of anaemia. Diseases and symptoms caused by a lack of vitamin B12 are an abnormal blood count, skin diseases, inflamed mucous membranes and uncoordinated movement.
Bird breeders should always ensure that their breeding birds have an adequate supply of vitamin B12, as a lack can cause the hatchability to sink to under 50%, and new-born birds are frequently deformed and display fatty degeneration of the liver, kidneys and heart.
Biotin (Vitamin H)
Reference books often refer to biotin as vitamin H. Biotin is part of the vitamin B complex and occurs mainly in the free form in yeasts and plant tissues, whereas in animal food sources it is usually attached to an amino acid, most commonly to lysine. Only small quantities of biotin can be found in many animal and plant tissues but animals need very little. Liver, kidney and egg yolk are the richest sources of biotin, but raw egg white contains the protein avidin which binds and inactivates biotin. Rancid fats or large amounts of unsaturated fatty acids in the food can also have a negative effect on the biotin supply.
Biotin acts as a coenzyme and is involved in protein synthesis as well as carbohydrate metabolism.
Characteristic symptoms of a biotin deficiency are changes in the skin, a rough coat and loss of hair. Crusty scabs between a bird’s toes and horn-like material on its bill or beak as well as sores can appear. Dogs often show neurological disorders if biotin is lacking in their diets.
Practically all foods apart from tapioca flour contain folic acid. Dried yeast, extraction of crushed soybean and fishmeal are particularly rich in this vitamin. As well as helping to build proteins and the cell nucleus, folic acid acts as an enzyme in the digestive system thus aiding intestinal absorption. Like vitamin C and vitamin B12, folic acid plays an important role in preventing anaemia and in building anti-bodies.
Almost all the vitamins in the vitamin B complex, including folic acid, are necessary to ensure healthy growth, and a lack of folic acid can lead to rough plumage, loss of hair, and disturbances in the propagation. Bird breeders often find that a folic acid deficiency can lead to poor hatching results after only 5 – 6 weeks.
Nicotinamide / Nicotinic acid (Niacin)
Both nicotinamide and nicotinic acid are effective as vitamins as the nicotinic acid found mainly in plants is changed to nicotinamide in the animal cells. Except in domestic cats and most insect species, the amino acid tryptophan can be converted to niacin by the body thus covering most of the body’s need of this vitamin in the vitamin B complex.
Nicotinic acid is sometimes known as vitamin PP, the abbreviation PP standing for Pellagra Preventive, as a lack of this vitamin can lead to this skin disease in Man, which can be fatal when untreated. A niacin deficiency is characterised by dermatitis, loss of weight, retarded, diarrhoea and disorders of the central nervous system. A deficiency of this vitamin in dogs can lead to blacktongue i.e., increased deposits of melanine in the mucous membranes of the tongue. High corn diets can cause a niacin deficiency due to a tryptophan deficiency in corn protein and the low availability of niacin in corn. Leg disorders, slipped tendons or perosis are frequently observed in birds whose diets contain too little niacin.
Except for tapioca flour this member of the vitamin B complex occurs in many foods of plant and animal origin, as the name indicates (pantothen = from all sources Gr.). Yeasts, liver, kidney, green, leafy vegetables and flour from green grain have a high content of this vitamin. As far as is known at the present time, pantothenic acid is a component of only one coenzyme, coenzyme A, which is required for the synthesis of fats and conversion of carbohydrates. Only the D isomer of crystalline pantothenic acid is usable by animals, and the calcium-D-pantothenic acid compound form has been used here in our diagrams to depict the microscopic and macroscopic picture.
A pantothenic acid deficiency leads to skin and hair lesions, gastro-intestinal troubles, retards the development of feathers and embryos and causes dermatitis in the area of the eyes, mouth, vent and feet in chicks. In some species a deficiency causes anaemia and general debility leading to reduced resistance to infection and parasites.
As pantothenic acid is required for the synthesis of cortical hormones, a deficiency may lead to necrosis of the adrenal cortex. It is essential that breeding birds receive enough of this vitamin at the very beginning of breeding as a deficiency can result in dead embryos or weak chicks.
Choline does not always count as an essential vitamin for all species of animals and is, in fact, a vitamin-like compound, being a structural component of fat and nerve tissue with a biological function. Most species can replace it through an adequate supply of methionine, folic acid and vitamin B12. It should be given in the first few weeks of a bird’s life (approx. 8 weeks), however, as young birds are not able to produce enough for their needs themselves. Most animal feeds, in particular commercial bird diets contain a higher percentage of choline than of other vitamins. Choline promotes growth and helps the reduction of fats.
Myo-inositol is another substance that cannot be classified as a true vitamin. but it does possess functional similarities to the vitamins.
Fully-grown animals can generally form enough myo-inositol for their needs from their normal diet. During growth, however, animals should be given an extra supply as they are unable to produce enough themselves.
Myo-inositol is found in most plant and animal tissues with grain heading the list of foods rich in this vitamin; which is the reason that poultry and other seed-eating birds rarely suffer from myo-inositol deficiency diseases. Myo-inositol is essential for growth and acts as a carrier for fatty acids. A lack of myo-inositol can lead to disturbances in the propagation, loss of hair and fatty degeneration of the liver.