HEMOCHROMATOSIS IN LORIES

Margrethe Warden

 

Hemochromatosis or Iron Storage Disease is a metabolic disorder that causes an unusually large amount of iron to be accumulated in body tissue. According to the Centers for Disease Control and Prevention (CDC), Hereditary Hemochromatosis in humans is one of the most common genetic diseases in the United States, affecting as many as one million people. The genetic factors that cause the disorder have been isolated. It is not only treatable but also in some cases preventable. While much is known about this disorder in humans one should be cautioned against drawing too many parallels in its effects on avian species. In lories it is a potentially lethal problem. In avian species the causes are unknown but veterinarians and aviculturists believe it to be a combination of several factors including diet, evolution and genetics. This disease has been most commonly seen in captive soft billed birds such as mynahs, toucans and birds of paradise and is rarely seen in these same species in the wild. It seems to occur more commonly in frugivores and insectivores. There is growing evidence to indicate that lories may also be a species vulnerable to this disorder.  Because they are becoming increasingly popular in the United States we are likely to see more and more incidents of hemochromatosis in our lories.

There have not been many studies conducted on avian hemochromatosis; therefore, much of what is commonly believed about the disorder is speculation. Most of the information relating to Iron Storage Disease and lories is anecdotal and, as such, is not always appropriate data for an actual scientific discussion. I began learning more about this condition back in 1999 when it was discovered in several of my own lories, specifically in five of my black lories (Chalcopsitta atra).

 

In most cases, hemochromatosis is asymptomatic until shortly before death. When evident, symptoms can include difficulty breathing, fluid in the air sacs, paralysis and distended abdomen. Actual diagnosis is usually made during a necropsy. In living birds, tests conducted on tissue retrieved from a liver biopsy can make a specific diagnosis. Radiographs and blood work on living specimens can indicate liver disorders that may include iron storage but will not accurately diagnose the disorder itself. Other tests may not be as helpful in determining status of hemochromatosis in a living bird. If diagnosed in a living bird, there are some treatments available, although many of the results are questionable. Phlebotomy, drawing blood equal to 1% of the birdís body weight on a regular basis, is acceptable treatment. It is not always a practical one, especially on aviary birds not used to being handled. Chelation is also a possible treatment. The drug Deferoxamine has been used experimentally on birds with limited success. Research using natural plant tannins is now in progress in different locations. The Riverbanks Zoo in Columbia, SC has been testing the use of tannins by giving tea to their toucan population; however, as of this writing the results are not available.

Iron is stored in the cells of the liver until it is needed to create hemoglobin. The storage of iron occurs most frequently in the liver but may involve other organs as well. The availability of dietary iron is considered to be a factor in the subsequent storage. Plants store iron in a tightly bound form known as phytochealates thereby reducing its availability. Animal products such as bone meal and blood have more bioavailable iron than plant material. The more available the iron is the more readily it can be extracted and stored in the tissue. Diets that contain animal protein sources can be higher in available dietary iron than those using plant protein sources. While plant sources are considered to have less available iron there is a school of thought which says that items such as grapes and bananas have a higher iron content than other fruits and should be avoided. Because they contain plant source iron, it is not likely this warrants great concern. Another factor that assists the absorption of iron is ascorbic acid, commonly found in citrus fruits. The acid can release the tightly bound iron from plants and make it more available. While many aviculturists have used citrus successfully, the use of it is something to consider when developing your total diet.

While diet can play a formidable role in the development of hemochromatosis, it can also occur when there are relatively low levels of dietary iron. Genetics must also be considered a factor. The predisposition to the disorder may be hereditary and passed on through certain bloodlines. Anecdotally, lories in the Chalcopsitta group (blacks, cardinals, Duyvenbode's and yellow-streakeds) seem to be more susceptible than some of the other species. Because this group of lories have, at times, existed in American aviculture in prodigious numbers, it is almost impossible at this point to trace the genetic link or differentiate the bloodlines. In a natural environment, dietary iron may be practically nonexistent in some regions and birds must adapt by becoming better able to process and store necessary iron. It is possible that lories have evolved into one of the species that process iron too efficiently thereby absorbing and storing all available iron. Kept in captivity, these birds are fed a diet that, even while it is considered to be low in iron, has a much higher iron content than that which would be found in their wild habitats. It also appears that birds who are prone to iron storage do not decrease the uptake of iron when the amount stored is adequate

This disorder usually shows up in lories around five or six years of age; however, it has been discovered in much younger birds than that who have consistently been fed a diet high in iron content. It is ultimately a fatal disorder that can take months, even years, to develop and become severe enough to result in death. The prevalence of iron storage in lories is not well documented; therefore, it is not known if it has become a common problem in our captive population. The lack of documentation underscores the importance of performing a complete necropsy on every lory that dies. A liver stain can diagnose iron storage. Even when iron storage does not appear to be the primary cause of death, it is important to conduct the histopathology to determine if the disorder was developing in the individual. Only through these tests and the compilation of information will the pervasiveness of this disease be documented and understood.

Hemochromatosis may not be a great concern to the average pet owner but it should be considered when keeping a collection of lories and also when selecting the diet most appropriate for ones birds. Maintaining the total dietary iron below 70 ppm (parts per million) can be effective in keeping this disorder to a minimum. During the summer of 1999 most of the commercial diets formulated for lories available to collectors and pet owners in the United States, along with some handfeeding formulas and monkey chow, were tested for total iron content at the University of Georgia. While the total nutritional value was not evaluated, it was found that the iron content in all the diets manufactured specifically for lories fell below 100 ppm. These diets did not all contain added iron but iron occurred naturally in many of the ingredients and occurs in the milling process as well. A good quality commercial product is often the base of a good lory diet. Add to that are an assortment of fresh foods. Certain foods such as peaches, plums, honeydew melon and apples without skin are low in iron. Bananas, mangoes, papaya, summer squashes, dark leafy greens and boiled potatoes without skin are a bit higher in iron content but can still be within the acceptable range. Foods to definitely avoid would 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.

Since most lory species are no longer being imported into this country, we must be diligent in maintaining the good health of the existing population.

Ritchie, Harrison, Harrison; Avian Medicine, Principles and Application
Darrel Styles, Hemochromatosis: A Metabolic Disease of Softbills,

Kirk Klasing, Comparative Avian Nutrition

Alicia McWatters, personal communication
Cheryl Greenacre DVM, ABVP, personal communication

Centers for Disease Control and Prevention,
Overview on Iron Overload and Hemochromatosis
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The two most prominent lory diets, as of November 2015 are Blessing's and Lory Life. 

As of 22 October 2015, Blessing's powder and nectar both tested as 49.2 ppm iron
As of August 2015, Lory Life nectar tested at 28 ppm iron.


Past history:

Commercial Products Tested for Iron Content in 1999

Product Iron content (ppm)

Pretty Bird 8% Handfeeding 101*
Kaytee Exact Handfeeding 374
Nekton Lori 71
Lories Delight 51
Roudybush Lory 93
CeDe 61
Monkey Chow 201
Nutribird 86
Lory Life Nectar 98*
Lory Life Powder* 84/82**

*Lory Life Powder was tested again in 2000 because it had subsequently been reformulated to contain less iron. Results revealed it contained 27.66 ppm (parts per million) iron. Tests were performed in 2002. The first showed two separate batches of powder as 77 ppm and 102 ppm and the nectar mix at 68. The second set of tests done in December 2002 showed Lory Life powder at 40.41 ppm and nectar mix at 32.36 ppm. Tests done from 2003 to present show Lory Life, both powder & nectar, within the 25ppm - 45 ppm range.

Pretty Bird handfeeding formula was also tested in 2002 and was 111 ppm.

* *Two separate batches were tested

In 1999 most of the feed samples and the bulk of the funding for testing were provided by the online community of Lory World.

 

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