Pelleted diet study..

[Mygala]

This is one of the best studies I've found recently.

Quote: Formulated Diets Versus Seed Mixtures for Psittacines Nutrition of Caged Birds Formulated Diets Versus Seed Mixtures for Psittacines1,2 DUANE E. ULLREY3, MARY E. ALLEN4 AND DAVID J. BAER5 Comparative Nutrition Group, Department of Animal Science, Michigan State University, East Lansing, MI 48824

http://www.scenicbirdfood.com/pdf/nu...cagedbirds.pdf

I'd urge you to read the whole thing.

Here are a few excerpts that I found particularly interesting:

Quote: Abstract- Psittacines are often classified as seed eaters despite studies that have established great diversity in food habits in the wild. While seeds are consumed, so are flowers, buds, leaves, fruits and cambium. Some psittacines consume parts of >80 species of grasses, forbs, shrubs and trees. In addition, insects may be important. Although there are few controlled studies of the requirements of psittacines, it is probable that most nutrient needs are comparable to those of domesticated precocial birds that have been thoroughly studied. Commercial seed mixes for psittacines commonly contain corn, sunflower, safflower, pumpkin and squash seeds, wheat, peanuts, millet, oat groats and buckwheat, although other seeds may be present. Because hulls/shells comprise 18-69% of these seeds and they are removed before swallowing, a significant proportion of typical seed mixtures is waste. Some of the seeds also are very high in fat and promote obesity. Common nutrient deficiencies of decorticated seeds include lysine, calcium, available phosphorus, sodium, manganese, zinc, iron, iodine, selenium, vitamins A, D, E and K, riboflavin, pantothenic acid, available niacin, vitamin B-12 and choline. Attempts to correct these deficiencies by incorporating pellets into seed mixes are usually thwarted by rejection of the pellets and disproportionate consumption of items that are more highly favored. An extruded diet formulated to meet the projected nutrient needs of psittacines was fed with fruits and vegetables to eight species of psittacines was fed with fruits and vegetables to eight species of psittacines for the 66% observed during the previous 2 y when these psittacines were fed seeds, fruits and vegetables. Although this extruded diet was well accepted in a mixture of fruits and vegetables and met nutrient needs, analyses have shown that not all commercial formulated diets are of equal merit. J. Nutr. 121: S193-S205, 1991.

I find this interesting. They did not "name names" as to which were the best and the worst. It does reinforce my belief that rotating brands may be beneficial. Especially, if some are better in some nutrients than others.


A couple more quotes ..somewhat out of context, but I think you'll get the gist..

Quote: Questions have been raised in the lay literature concerning the appropriate amount of dietary protein for psittacines, and some have suggested that a protein percentage in the low to mid 20s may be harmful. The implication is that these levels of protein overwork the liver and kidneys and may cause gout..... Undoubtedly, adult psittacines that are not in a breeding colony or from whom young birds have been removed for hand rearing have lower dietary protein and amino acid requirements. However, the minirnum requirements for maintenance of adult psittacines have not been determined. Unfortunately, the adult pet nonbreeding bird is most likely to be fed items that are not nutritionally complete. If appropriately compounded formulated diets are diluted with treats, the nutritional strengths of the formulated diet will help compensate for the nutritional weaknesses of the treats. On the other hand, if formulated diets contain only the minimum maintenance requirements, nutritionally imbalanced treats cannot be regularly fed without endangering health..... What if an adult nonbreeding psittacine is fed only a nutritionally balanced diet, such as the extrusion inTable 11, without dilution with other foods? Will its liver and kidneys be overworked and will it get gout?.... However, no one has been able to induce primary liver or kidney damage in normal birds by feeding a nutritionally complete diet containing high levels of well-balanced protein..... If the diet is also deficient in vitamin A, as a seed diet is likely to be, there may be sufficient renal damage to interfere with uric acid elimination, causing an elevation in blood uric acid concentration and resulting in urate deposits in the kidneys and ureters (33). A number of drugs also have been shown to influence uric acid excretion (34, 35). It is apparent, then, that gout in birds is a multifactorial disease. A diet that is deficient in protein, specific amino acids or vitamin A is potentially much more damaging than a properly formulated diet that may provide somewhat more protein than needed for maintenance. Despite the advantages of a well-formulated diet for psittacines, there are large deviations between the nutrient concentrations of a number of commercial products, advertised as nutritionally complete, and the probable nutrient requirements of birds to which they may be fed. When 11 diets from eight manufacturers were analyzed, both nutrient deficiencies and excesses were revealed (36). Of 18 analytical values for each product, the following nutrients and their indicated concentration ranges (dry basis) were particularly disturbing: (in g/kg) crude protein, 150-310; calcium, 1.8-15.4; phosphorus, 2.9-10.6; calcium/phosphorus ratio, 0.62-1.97; sodium, 0.3-4.1; (in mg/kg) iron, 80-4200; copper, 8-132; zinc, 31-939; manganese, 15- 1055. These ranges include values that are low enough to produce clinical signs of ill health. Notable are the low values for calcium, phosphorus, sodium, zinc and manganese. High values that may lead to clinical signs of toxicity include those for iron, copper, zinc and manganese. An inverse calcium/phosphorus ratio would impact adversely on the metabolism of these two elements. Some of the other extreme values may not produce specific clinical signs but may impair growth and reproduction. Since analyses for amino acids and vitamins were not performed, it is possible that a number of additional nutrients may have been present in deficient or excessive (37) amounts. Thus, it is important that the nutrient specifications of commercial formulated diets be carefully reviewed (and confirmed) before they are used.

The conclusion I draw from this, is that pelleted diets are the best available diets for captive psittacines. They are not all equal. Reading the label and know what you read are important.
Being aware that each may not be 100% perfect for each bird, would encourage me to rotate my brands to "even out" any deficiencies or excesses that may be present, especially since the amino acid breakdown or the various proteins is not available on the packaging, ...and most of us wouldn't know which aminos we need to look for anyway!

Just something for your perusal...

Edit: I would add that this article, though very thorough, was publishished in 1991 ...I have no doubt that the science and techological advancements in avian nutrition have made the basic pelleted diet on the market now, MUCH more consistent and nutritionally balanced than when this article was written.
Bob