Practical avian nutrition (Proceedings)
Nutrition is the process by which birds and all other animals consume food items and utilize it in the body for growth, tissue replacement or repair and the continuance of life. Good nutrition is crucial in optimizing health and preventing disease. With companion birds, nutrition must have great prominence in an overall program of wellness and health.
To examine avian nutrition the topic can be approached from the standpoint of defining nutrients and listing their importance to the different aspects of the bird's cellular and metabolic functions. Many of these avian nutrition points are provided in this lecture presentation. An additional and perhaps more interesting way of learning about avian nutrition is to examine the practical aspects of feeding birds. By evaluating and considering the different types of diets fed, recommended and available, certain principles will become apparent, helping the avian client to provide the very best diet available.
There are several main types of diets which are typically fed to pet birds. Each diet has similarities, but it is often the differences which yield the greatest amount of information. The clinician should keep in mind that different diets may work well some situations, but not all. One must consider how a diet can fit into the client's lifestyle as well. There are five major diet types available to pet birds: seeds, supplemented seed diets, seeds with fruits and vegetables, table foods, and manufactured (extruded/pelleted) diets.Seeds are often considered by some to be the natural diet for pet birds. Certainly, many birds eat seeds in the wild, but the seeds found in the pet store, unfortunately, are not the common seeds eaten in the wild. It is nearly impossible to provide pet birds with the food for which they forage in the wild. Birds in the wild are quite different from domestically raised birds. Pet birds do not have to search for their food, nor do they have the same need for high fat, high energy foods as wild bird. Pet birds simply do not have same pressures in the home environment as they would encounter in the wild.
Seed diets are sold as a common and inexpensive food to pet birds. Pet birds readily consume seeds and there is often no difficulty in converting a bird onto this type of diet. Simple seed diets may contain a few or several different seeds (they often have a proso millet base). If no supplementation is added to the diet, then a seed only diet is not adequate for pet birds. Seeds lack several key nutrients including vitamin A, vitamin D, vitamin B12 , calcium, several trace minerals, and essential amino acids (lysine and methionine in particular, two crucial protein building blocks). Several disease syndromes are directly related to these deficiencies and can be characterized simply by the physical appearance upon examination of the bird.
An example of a deficiency syndrome arising from a seed only diet can be seen with vitamin A. As the skin and tissues around the mouth, nares, eyes and gastrointestinal tract develop, essential vitamins are needed for normal growth. A seed only diet cannot provide that essential vitamin A or vitamin D either, because it simply is not present to be utilized. Consequently, abnormal tissues develop (such as blunted choanal papillae) which can lead to poor health and disease. Clinical signs of vitamin A deficiency in birds include hyperkeratosis of the nasal passages, oral mucosa, conjunctiva and respiratory tract. Retinal degeneration has also been documented with vitamin A deficiency.
Calcium is another important nutrient for birds. A seed diet contains very little calcium. Without adequate calcium bone development and integrity is affected. Female birds which are reproductively active on a calcium deficient diet often have egg or reproductive abnormalities such as soft-shelled egg production or egg binding. Providing essential nutrients in the proper ratio and amount is crucial as well for nutrient uptake. In the absence of vitamin D and the mineral phosphorus, the calcium is of little value. Seed diets are inherently high in fat which can lead to obesity, lipoma formation and hepatic lipidosis in susceptible species.