The Importance of Avian Nutrition

Despite all the information that we currently possess regarding avian nutrition, the sad fact is that many bird owners are still feeding their pets a completely inappropriate diet. I am still surprised at the number of cases of hypovitaminosis A that I see. Malnutrition and other diet-related diseases are far too common in my practice, and I'll bet they are in yours, as well. How do we handle the complex subject of nutrition when it comes to our avian patients?

Each and every avian patient that comes into a veterinary clinic should have a thorough history taken, even those that just come in for grooming. The reasons for this should be obvious. Birds on a poor plane of nutrition are at risk for pathologic fractures during routine wing clipping and nail trimming. Every owner who brings a bird in should receive some counseling about nutrition. At the least, they should be given a hand-out on nutrition. (The Association of Avian Veterinarians offers for sale an excellent pamphlet on feeding pet birds, which I highly recommend).

Clients armed with this new information on the proper diet for their pet bird should be instructed that it can be dangerous to abruptly switch a bird's diet without first allowing the vet to perform a complete physical examination and testing. Uncovering subclinical illness prior to the stresses involved in dietary changes is vital to prevent a chronic illness from precipitating an acute health crisis. The process of conversion from seed to pellets is beyond the scope of this paper. There are several different methods to convert a bird over to a better diet.

Hypovitaminosis A is the most common problem seen in birds that consume primarily a seed diet. What owners and vets must realize, is that even if a bird is offered the essentials of a balanced diet, it is likely to pick out and consume what it likes best, and not necessarily what is good for it. Hypovitaminosis A is often easy to diagnose. Usually, the choanal papillae will be blunted or absent. Often, white plaques may be visible in the oropharynx (these are usually Candida lesions). On a Gram's stain of the choanal slit, there may be excessive numbers of epithelial cells, as well as yeast (often budding). Treatment should include parenteral administration of vitamin A and D3. Remember that vitamin A can be toxic if overdosed, so injectable vitamin A must be carefully dosed. As a supplement, beta-carotene is non-toxic, as the body will convert what it needs to vitamin A and the rest will be excreted unchanged. Beta-carotene (in the form of a liquid gel capsule) may be supplemented orally (by snipping off the tip of a capsule and administering a drop or two directly into the oral cavity or on a piece of food) or an avian preparation powdered vitamin containing vitamin A can be sprinkled on soft food. I don't recommend putting vitamins in the drinking water, as they tend to make water less palatable, they may oxidize and bacteria may proliferate in it. If there are any secondary infections (with yeast or bacteria), then those should be treated appropriately, as well. [I have found that using only nystatin orally, which isn't absorbed systematically, and thus, only will treat yeast it comes in direct contact with, is only effective in about 40% of candidiasis cases. I use a combination of diflucan (Fluconizole) 100 mg. crushed and mixed with 20 cc. of nystatin oral suspension, dosed at 0.5 ml. per 1000 grams body weight PO BID 5-10 days. I find this combination is very efficacious and safe for stubborn candidiasis cases. It is though to be stable at room temperature for up to 6 months.]

Once a bird has been diagnosed with hypovitaminosis A, based on the history, diet, appearance of the choanal papillae and Gram's stain results, treatment will result in a rapid resolution of clinical signs. I recommend that you get used to examining the choanal slit with a bright light source and magnification, in order to accurately evaluate the appearance of the oropharynx. By using a strong light and magnification, you will be able to examine the choanal slit of even cockatiels and budgerigars. While any species of psittacine can develop hypovitaminosis A, in my practice, I see it most often in Amazon parrots on an all-seed diet. Eclectus parrots have historically been thought to require higher levels of vitamin A than other species, however, I rarely see clinical hypovitaminosis A in them.

While peanuts are often given as a treat to parrots, and they are commonly found in seed mixes, I don't recommend the routine feeding of peanuts to psittacines. There is a risk of aflatoxicosis from peanuts (and also from corn and other grains). The mycotoxins cannot be seen, tasted or smelled, and they can be present in both raw and roasted peanuts. While commercial peanut butter is very safe (as the government requires testing for aflatoxins), peanuts are probably best avoided altogether or given very sparingly. Almonds are a much better treat, as they are higher in calcium, and not being grown in the ground, safer to feed.

In their natural habitats, budgerigars and cockatiels are primarily seed-eaters. It has been my experience, and that of many of my colleagues, that these birds are more prone to renal disease if they are fed a 100% pelleted diet long-term. We are seeing more and more budgies and cockatiels that are 6-10 years old and suffering from kidney problems. Many of us feel that it is better to offer a percentage of pellets, a percentage of seed (especially millet and sprouted seed) and a variety of fresh foods (bread, cooked pasta, brown rice, legumes, vegetables, fruits and other table foods). While it is certain that a pelleted diet is by far superior to a diet comprised of seed, we must be aware that many of the formulated diets haven't been proven for the life expectancy of so many species. For example, my husband owned one cockatiel for 28 years! There may also be other contributory factors to renal disease, such as chronic, subclinical chlamydiosis.

Many pet stores feel that offering a diet based on safflower seed is superior to a sunflower seed diet. There are many myths still floating around about the dangers of sunflower seed. Both sunflower and safflower seed are high in fat, and low in about every other nutrient, but there is no addictive ingredient in sunflower seed! Since safflower seed is more bitter, birds tend to eat fewer of them than sunflower, if given the choice. Many seed mixes are vitamin fortified. However, the vitamins are usually in the shell, so when the seed is hulled, the fortification is lost. Seed mixes with some added pellets are better, however, often the birds just throw out the more nutritious pellets, and selectively eat the seeds.

Sprouting seed can make a diet healthier. The process of sprouting utilizes some of the fat stored in the seed, and the sprouted seed may accustom the bird to eating some vegetables.

The newest trend in formulated diets is the tailoring of a diet to specific species of groups of birds. Lory diets have been available for quite some time, as they have specific and unique dietary requirements. They consume high quantities of nectar, and lory diets have been developed that can be mixed with water, and others have been designed to be offered dry in an attempt to decrease the loose, liquidy droppings.

Diets have been developed for birds that are preparing to breed. These diets are generally higher in nutrients to simulate the abundance of food that often precedes the breeding season. These diets can be fed through the breeding season to support a pair of birds that are feeding their offspring.

Different formulated diets have been developed for different species of birds. Manufacturers have also designed diets that are helpful for overweight, sedentary birds. However, one manufacturer recommends feeding their high-potency diet for overweight Amazons, on the assumption that because the nutrients are more concentrated, the bird will become satiated more quickly and thus, will eat less. In some cases, it is important to limit the amount of food offered daily to prevent obesity.

There are diets designed for juvenile birds. These are meant to provide the extra nutrients necessary for proper growth and feather formation. Birds should be switched to adult formulations according to the manufacturer's recommendations.

Diets have also been developed that are low in iron. These diets are designed for the bird diagnosed with iron storage disease, hemochromatosis, or for species of birds that are known to have problems with iron storage disease. Dr. Gwen Flinchum has diagnosed several cases of iron storage disease in older Amazon parrots with abnormal black feathers, and these parrots will benefit from a low iron diet, as well.

Water is a very necessary part of avian nutrition. Fresh, clean water should be available at all times. However, if an owner is providing a water bowl, this is often easier said than done. Many birds with water bowls tend to dump all of their food into the water, and they may defecate into the water, as well, creating a nasty soup that grows bacteria rapidly. I see many more cases of subclinical bacterial infections in birds with water bowls. For this reason, I recommend that all parrots be converted to water bottles, if possible. Parrots are so smart that they usually figure out how to use one in short order, and this prevents the mess and associated risk of bacterial infection (as well as problems with Giardia, and ascarids, both of which have a direct life cycle in birds). If tap water has high mineral content, bottled water should be offered. Birds with iron storage disease should not drink tap water that is known to have high iron content.

Avian nutrition is a constantly evolving area of avian husbandry and medicine. As we learn more about the intricacies of diet, we will be better able to counsel our clients about providing a healthy and appropriate diet for their pet and breeder birds.

Cadeusus
Copyright 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
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