|Vitamins and Birds
By James M. Harris, BS, DVM, FRSH
Mayfair Veterinary Clinic, Hobart
Vitamins are trace nutrients. They function as either cofactors
or hormones. Vitamin E is an exception as it acts as an antioxidant.
Vitamins are divided into fat and water-soluble groups. Fat stored
vitamins have greater storage times, as they are soluble in lipids
Found in many fruits and vegetables, it is missing in seeds. It has
benefits to vision and the health of mucous membranes. Deficiencies
can result in sinus infections as the tissue, weakened without it is
less able to resist bacteria. It is stored in the liver.
Vitamin D3 is the form of vitamin D used by birds. It is synthesized
from a compound in the skin when the skin is exposed to ultra violet
light. If birds are exposed to unfiltered sunlight the do not need
to be supplemented with vitamin D. The main effect of this vitamin
is the mineralization of bone. Deficiency during growth results in
rickets. In adult birds, soft-shelled eggs or thin-shelled eggs are
formed. If there is long term deficiency in egg laying hens, bones
demineralize and the result is osteomalacia.
Vitamin E functions as an antioxidant, interacting with the mineral
selenium to assist in the healing of oxidized tissues.
The primary function of this vitamin is its role in the clotting of
blood. It also appears to play a role in bone formation, deficiency
resulting in skeletal deformities.
Water-soluble vitamins are required in the diet because they are
cofactors for enzymatic reactions essential for normal metabolism.
They cannot be made by the individual. They have short storage times
and must be provided regularly.
Thiamin is found in grains so deficiencies are very rare. Polished
rice is deficient in B1. Some fish have an enzyme that destroys B1
and should not be fed as an exclusive diet to fish eating birds.
Deficiency results in neurological signs.
Riboflavin is necessary for normal growth in chicks. A deficiency
manifests as retarded growth, diarrhea and leg paralysis. It is also
necessary for egg production. Chickens fed deficient amounts have
reduced egg production. Seeds are deficient in B2.
Niacin is formed from tryptophan. Corn and millet diets are
deficient in this vitamin. Pellagra (black tongue) in chickens is
the result of niacin deficiency.
Biotin deficiency is associated with wheat and barley diets. Fatty
liver and kidney disease is seen in chickens. Other signs of biotin
deficiency are dermatitis of the feet, necrosis of toes, jaw
deformities, and swollen eyelids.
Folic acid is involved with carbon metabolism. It is a cofactor in
the synthesis of purines. Uric acid, the white powder in a bird's
droppings, is the main purine produced by birds and is the method by
which nitrogen is excreted. Folic acid is found in many foods.
B12 is not found in adequate amounts in plants. It is known as the
animal protein factor". It is stored for long periods of time in the
liver. B12 should be supplemented in birds fed only plant diets.
Pantothenic Acid is a component of coenzyme A. It is found in seeds
and is unlikely to be a dietary deficiency.
B6 is essential in a number of reactions related to nitrogen or
amino acid metabolism. Deficiencies are unlikely on varied diets
Ascorbic Acid (C)
Most birds make C from glucose. Vitamin C is involved with the
production of collagen and elastin in blood vessel walls. A
deficiency will result in hemorrhage. Willow ptarmigan and bulbuls
need to be supplemented. If in doubt Vitamin C can be supplemented
as it is not toxic.
(Note) All the nutritional study in birds has been done on the
domestic chicken which has great economic importance. Little is
known about the needs of wild birds. Birds in the wild do not
receive supplemental vitamins. They obtain their vitamins from their
natural diet. It is difficult to feed each species kept in captivity
its natural diet. For that reason if in doubt, I would recommend
supplementing avacultural and pet birds with a good quality avian
Copyright remains with author.
RETURN TO ARTICLES