Information Series

HARI was established in 1985 and continues to evolve into a world class Psittacine captive breeding, nutrition anddisease research facility. Present staff includes the Director, Mark D. Hagen, M.Ag., Consulting Veterinarians Dr. Louise Bauck, Dr. Michael Taylor, three Veterinary Technicians, and three Livestock Attendants. The range of fifty parrot species at HARI is a good representation of parrots currently in captivity. Work is continuing on new diets, healthy treats, and supplements for those birds. The breeding and disease research is shared with breeders all over the world and HARI staff have spoken at all major US avicultural conferences.

The most dramatic nutrient problem with seed based diets is not a deficiency but an excess of fat. Fat levels in the three most commonly eaten seed kernels are so high that these seeds are referred to as "oilseeds". Although safflower is a smaller and less palatable seed than sunflower, its fat content is, in fact, higher than sunflower. Birds may not like the bitter taste of safflower and tend to eat a larger variety of seeds when eating a diet based on it. High fat intake results in abnormally small compact stool and low water intake since water is a by-product of fat metabolism. Formulated diets produce much larger stool, especially lower fat pelleted diets where birds also drink more. Tropicanhas the correct balance of fat, not too low but still one fifth the levels found in oilseeds.

The caloric density of a diet is important because this is what determines how much food the bird will ultimately eat. The energy level also determines how much vitamins, minerals and protein the bird will receive on a daily basis from the ingested food. More pelleted food needs to be eaten by birds to maintain their weight, in fact almost twice as much as high calorie seed kernels. Fat has more than twice the energy value per gram than protein or carbohydrates and this accounts for the energy differences. The cost of feeding a bird is not based on the price per kilogram of food but the price per kilocalorie of digestible energy. Extruded Tropican has balanced its higher digestibility and higher energy value versus pellets producing a very economical diet.

The quality of protein, that is its amino acid balance, is as important as the total level in a diet. Tropican contains seven different grains and nuts; the largest variety of any formulated bird food. Besides the obvious palatability advantages of this mixture of ingredients, benefits to protein quality also occur. The different amino acid profiles of these various protein sources complement each other, resulting in a premium protein of high biological value. Some concern has been expressed over birds receiving too much protein and thus stressing nitrogen excretion organs (a by-product of protein metabolism). Remembering the total amount of protein consumed by the bird is dependent on the energy density of the food, we must therefore divide protein by the calories to get a meaningful comparison of various diets.

As mentioned, the high calorie nature of oil seeds limits their consumption and thus lowers the amount of amino acids available for growth of new feathers, muscles, etc. So, although oilseed kernels have a higher concentration (%) of protein, birds do not receive enough protein, which explains the poor feather growth in birds eating oilseed based diets. And conversely, birds may be processing too much protein on pellet type diets as a by-product of having to consume more of these diets to meet their energy needs. This concept of expressing nutrient levels based on dietary energy values is used by NRC for all animal nutrient requirement publications. Once again, Tropican has balanced protein with energy, not having too much or too little.

Fiber levels in seed kernels are much lower than what is declared on analysis statements on bags of mixed seeds. Since birds hull off the husks of seeds and nuts, these high fiber shells are not eaten by the birds but must be included in the whole bag analysis for packaging. Further selection by birds of the high calorie seeds and rejection of lower fat grains (which would balance out the fat) results in malnutrition and obesity. Formulated diets balance fiber with other nutrients in a pre-mixed kibble where birds cannot select out the higher fat ingredients. The mess around cages from high fiber hulls is a negative aspect of bird keeping, also eliminated with a formulated diet. Food used as a play toy is wasteful and unhealthy. Giving wood, rawhide and rope chew toys is far better for the long-term health of birds.

Common problems in birds on seed based diets are poorly calcified eggs and egg binding, weak bones, thyroid and muscle contraction problems. These are all related to the lack of several minerals in seed kernels. Simply producing a supplement for seed based diets that contain a little of each essential mineral is ignoring the fact that some minerals may already be at high enough levels in seeds. Potassium and iron are two minerals which are found at good levels in seeds. Too much iron supplementation may cause liver disease in some types of toucans, mynahs and other softbills. A closer look at each mineral deficiency is needed to prepare a proper supplement.

It appears that phosphorous levels in most grains and oilseeds are sufficient. Some of the phosphorous is unavailable to the bird as it is bound up with phytic acid. The ratio of phosphorous to calcium needs to within a range of about 1:2, that is twice as much calcium versus phosphorous. Most mineral supplements for birds contain this ratio but, when combined with high phosphorus, low calcium seeds do not result in the correct dietary intake. Hagen's Prime is the only bird supplement that uses calcium as a nutritive carrier and at levels which ensure birds not only receive this important mineral but also that the ratio with phosphorous in the final diet is correct.

Calcium levels in oilseeds are so low that African Grays, after just a few years on seed diets, may develop muscle tetany or other problems. These Grays would need emergency veterinary calcium supplementation as they have difficulty utilizing bone sources. Unfortunately, excessive calcium and its related nutrient vitamin D3 became a problem as breeders oversupplemented diets. In rapidly growing babies, calcium is deposited in soft tissue such as kidneys. Organ failure would result, illustrating the point that home made mixtures of food can be dangerous. Formulated diets that have strict quality control on nutrient levels are far superior for birds. Tropican has been on the market for over ten years with excellent results. Prime vitamin/mineral supplement was developed by HARI for those birds still eating seed and soft food diets, but dosages must be followed carefully.

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