Avian nutrition has greatly improved in recent decades but remains a common problem for pet birds. Formulated diets in pellet form and even organic formulated diets are now available, and domestically raised birds generally accept these readily. However, the nutritional requirements for individual species are still largely unknown. Many birds are still fed inadequate diets. The two most common reasons for malnutrition include allowing birds to choose what they want to eat from mixtures of seeds and nuts and pellets or feeding a pure seed or seed-based diet. Many of the illnesses seen in pet birds have their basis in malnutrition. These include liver disease, kidney insufficiency, respiratory impairment, musculoskeletal disease, and reproductive problems.
Some special nutritional concerns in pet birds should be noted. Mold that contaminates improperly stored seed and pet-grade peanuts can cause liver disease, so be sure that any feed is fresh and is properly stored.
Be aware of what your bird actually eats and drinks. Many owners provide a varied diet for their birds to eat (such as table foods, formulated pelleted diet, vegetables, and other foods), but fail to realize that what the birds actually consume is mostly seeds, which can lead to nutritional deficiencies and imbalances. Birds that are eating a predominantly formulated diet do not typically need additional vitamin or mineral supplements, unless prescribed by a veterinarian. Birds that are eating mainly seed diets should be transitioned slowly to a nutritionally complete formulated diet and may need supplements until the transition is accomplished. Powdered supplements should not be sprinkled over seed, because most birds remove the outer seed hulls before ingesting the kernel; therefore, they don’t benefit from the supplement. Supplements should not be placed in drinking water, because they either deter birds from drinking by changing the taste of the water, ultimately leading to dehydration, or they degrade once placed in water. To have any beneficial effect, supplements must be placed on moist foods that birds are likely to consume.
Obesity
Obesity is common in companion birds. High-fat diets (seeds, nuts, and many table foods), overabundance of food, and a sedentary lifestyle are all contributing factors. Obesity is defined as a bird being 20% over its ideal weight. Galahs, macaws, Amazon parrots, and quaker parrots are prone to obesity. Signs may not be evident, but obese birds may become lame or have difficulty breathing due to excessive weight and fat.
Obese birds should be fed a pellet diet with portion control. Exercise should be encouraged by providing a larger cage with multiple, dispersed food bowls to encourage movement. Rope or spiral rope perches will encourage climbing and balance. A flight cage outdoors should be provided for flighted birds, with walking or climbing stairs encouraged for nonflighted birds. Obese birds are more prone to develop arthritis, fatty liver disease, coronary artery disease (atherosclerosis), and heart disease.
Vitamin A Deficiency
A deficiency of vitamin A frequently goes unrecognized in pet birds. Birds that eat a substantial portion of their diet as seeds and nuts are most prone to this problem. Seed- and nut-based diets are deficient not only in vitamin A but in numerous other vitamins and minerals, as well as contain excess fat. Attempts to supplement with dietary vitamin A may lead to over-supplementation and serious side effects, including reproductive problems, bone abnormalities, and liver disease.
The diets of all pet birds should be evaluated for vitamin A and vitamin A precursor content. Vitamin A deficiency may be the underlying cause of chronic conditions such pododermatitis (inflammation of the soles of the feet), sinusitis, and conjunctivitis. Birds with reproductive disease on poor diets should be considered deficient.
Signs of vitamin A deficiency depend on which organ system is affected (for instance, the reproductive, digestive, or respiratory tracts). Signs include nasal discharge, sneezing, swelling around the eyes, difficulty breathing, increased drinking and urinating, poor feather quality, feather picking, and anorexia. White plaques may develop in and around the mouth, eyes, and sinuses. The spots ultimately become infected, forming large, obvious abscesses. The abscesses can distort the glottis (opening of the windpipe), causing labored breathing and eventually suffocation. The abscesses can even grow so large that they block the choana (the slit in the roof of the mouth). When this happens, the bird will exhibit profuse nasal discharge and obvious swelling around the eyes.
The best preventive against vitamin A deficiency is to provide a formulated diet with sufficient, but not excessive, vitamin A precursors. A precursor is a substance that can be converted into vitamin A in the body. These precursors, such as beta-carotene, are much less likely to cause the toxicity that can occur with excessive vitamin A consumption.
If your bird is not on a formulated diet, foods containing vitamin A or its precursors include cantaloupe, papaya, chili peppers, broccoli leaves and flowers, sweet potatoes, turnip leaves, collards, endive, butter, liver, egg yolks, beets, dandelion greens, and spinach.
Iodine Deficiency
The thyroid gland in birds sits within the chest cavity and is not palpable in the neck, as it is in humans. When fed an all-seed, iodine-deficient diet, this gland swells and presses on the trachea (airway) and esophagus – a condition called goiter. Classic signs include loud or harsh breathing, wheezing, clicking, and a voice change. Regurgitation occurs in severe cases. Affected birds tolerate stress poorly. Lugol’s iodine (1 drop per 1 cup [250 milliliters] of drinking water) can be used to treat the deficiency until the bird is transitioned to a nutritionally complete formulated diet.
Calcium, Phosphorus, and Vitamin D Imbalance
Seed diets are known to lead to an imbalance in the calcium to phosphorus ratio in birds, as well as creating amino acid deficiencies. This ratio is important because calcium, phosphorus, and vitamin D3 work together to perform vital functions, and a lack of or excess of any of these nutrients can affect the body’s ability to use all of them. Sunflower seeds, which tend to be preferred by many pet birds of the parrot family, are low in calcium, deficient in amino acids, and high in fat. Safflower seeds are actually higher in fat content than sunflower seeds, contrary to popular belief, and also contain inadequate amino acids and calcium. Providing a nutritionally sound diet that includes only a limited amount of seeds and nuts will help prevent these imbalances.
Vitamin D is made in the skin in response to ultraviolet light exposure. Adequate dietary vitamin D is essential to the proper absorption of dietary calcium, and diets lacking calcium, along with insufficient access to direct sunlight, can lead parrots to develop metabolic bone disease. In this condition, also known as nutritional secondary hyperparathyroidism, birds’ bones become soft and malformed and fracture easily.
Acute Hypocalcemia in African Grey Parrots
Acute hypocalcemia, caused by deficient levels of calcium in the blood, is more commonly seen in African grey parrots on all-seed diets and is characterized by weakness, tremors, and seizures. The exact cause is unknown, although parathyroid hormone abnormalities are suspected. Treatment with injectable or oral calcium may lead to immediate improvement. To treat this condition, veterinarians may prescribe calcium supplements and exposure of the affected bird to several hours of ultraviolet (UV) light daily. Exposure to UV light is critical to formation of vitamin D in skin, which, in turn, is essential to the absorption of dietary calcium. UV bulbs (not the same as plant lights or bulbs for reptiles) are available that emit light specifically in the part of the UV spectrum that birds require to make vitamin D.
Vitamin D Toxicosis
Although excess calcium intake is not thought to cause problems in most cases, excess vitamin D3 can cause harmful calcium accumulation in tissues such as the kidneys. Supplements should be used carefully, and excess vitamin D3 should not be given to susceptible species, such as macaws.
Iron Storage Disease
Iron storage disease occurs when too much iron accumulates in the liver. The body needs a certain amount of iron to produce hemoglobin, which is the molecule that transports oxygen molecules from the lungs to all the other cells in the body. However, when too much iron builds up, the body begins to store it in the liver, then the heart, lungs, and other organs, where it can do significant damage, eventually leading to death. Death may occur without previous signs.
When signs do occur, they include weight loss, depression, distended abdomen with fluid accumulation, difficulty breathing, and circulatory failure. Diagnosis is by liver biopsy. Treatment may involve periodic removal of blood, trapping free iron, and dietary modification.
The condition is common in pet mynahs and toucans, as well as certain zoo birds such as the bird of paradise. It has also been reported in pet birds of the parrot family, particularly lories. Although iron storage disease seems to be associated with excessive intake of dietary iron, not all birds become affected when kept on similar diets. Stress or genetic factors may also play a role. Certain foods rich in vitamin C, such as citrus fruits, increase dietary iron uptake. Excessive vitamin A consumption may also be involved.
Species such as mynahs, lories, lorikeets, and toucans are prone to develop iron storage disease when consuming high levels of dietary iron. They should be fed commercially formulated diets containing iron at levels < 100 ppm of diet and should not be fed citrus fruits. Certain foods such as peaches, plums, honeydew melon, and apples without skin are low in iron. Bananas, mangoes, papaya, summer squashes, and boiled potatoes without skin are a bit higher in iron content but can still be within the acceptable range. Foods to avoid include baby foods and juices and nectars that contain iron, foods that are enriched with iron or ferrous sulfate (including table scraps), animal products, such items as primate biscuits, and large quantities of citrus fruit.
For More Information
Also see professional content regarding nutritional disorders of pet birds.
