Iron intake and digestion in Cercopithecinae a comparison of methodsW. Arnhold1,2, M. Anke2, A. Bernhard3, K. Eulenberger3, G. Krische4, S. Goebel5
1BASU-Minerals, Inc., Bad Sulza, Germany, 2Friedrich Schiller University, Biological-Pharmaceutic Faculty, Institute for Nutrition and Environment, Jena, Germany, 3Zoological Garden Leipzig, Leipzig, Germany , 4Leipzig, Germany, 5 University Leipzig, Institute for Transfusional Medicine, Leipzig, Germany
Iron belongs to the essential trace elements for animals and humans. The mean daily intake of heme and nonheme iron varies between 5 and 47 mg in humans. Whereas nonheme iron is absorbed from 2 % to 20 % from the diet, the heme iron absorption is obviously better (5 to 35 %) (Beard and Dawson 1997). Furthermore, the Fe absorption depends on the individual Fe status and the ratio of promoters and inhibitors. Since the knowledge of the Fe intake and digestion has been increased in humans the analysis of the trace element supply of Cercopithecinae and the estimation of the Fe digestion and the Fe status has become necessary.
The trace element intake was determined in 24 clinically healthy individuals of 5 species of Cercopithecinae kept in 8 groups in Leipzig Zoo. The animals were given 4 meals every day. Following the duplicate method, quantitatively and qualitatively identical samples of the offered feed as well as feed residues and faeces were registered (n = 7 per group) on 7 successive days. Thus, it was possible to determine the consumption of the different kinds of feed and the Fe intake of these species. After dry ashing at 450 ºC the trace elements were determined with ICP-OES.
The determined Fe intake was compared to the calculated Fe consumption of guenons and lion tailed macaques and with the Fe intake and digestion of people with mixed diets and vegetarians. The iron status was estimated by blood parameters.
The feed dry matter contained an up to three times higher concentration of Fe compared to humans' mixed and vegetarian diets. Although the mean body mass of the animals only amounted to 8 % of the body mass of humans, they had a mean daily dry matter intake of 16 42 % and a mean daily Fe intake of 48 128 % of that of humans. However, when the daily trace element intake was related to the metabolic body mass an up to 9 times higher concentration of Fe was found in the diet of Cercopithecinae than in humans. Since the animals were clinically healthy and since the reproduction was not disturbed, a mean content of 60 mg Fe kg feed dry matter is regarded as meeting the requirement.
99518 Bad Sulza
Excessive iron storage in captive omnivores? The case of the coati (Nasua spp.)M. Clauss1, T. Hìnichen2, J. Hummel1,3, U. Ricker4, K. Block5, P. Grest6, J.-M. Hatt7
1Institute of Physiology, Physiological Chemistry and Animal Nutrition, Munich, Germany, 2Institute of Veterinary Pathology, Munich, Germany, 3Zoological Garden Cologne, Germany, 4Zoological Garden Schwerin, Germany, 5Animal Park Sassnitz, Germany, 6Institute of Veterinary Pathology, Zurich, Switzerland, 7Department of Zoo Animals and Exotic Pets, Zurich, Switzerland
In mammals, reports on excessive iron storage mostly focus on herbivorous animals. Yet, in birds, problems with excessive iron storage are mostly reported in frugivorous and/or insectivorous species. Lowenstine and Munson (1999) mention regular findings of excessive iron deposits in coatis, mammalian omnivores belonging to the carnivora. The natural diet of coatis is well documented, consisting mainly of fruits and insects, with very little vertebrate meat. In contrast, captive coatis are often maintained on dry or canned dog food, or receive mice or day-chicks on a regular basis. This means that they receive diets high in heme iron (from haemoglobin); although free-ranging insects might have high iron levels as well, they do not contain heme iron. As heme iron is absorbed much better than non-heme iron, the diet of captive coatis might therefore be characterized by very high levels of available iron when compared to the natural diet of these animals.
In order to corroborate the report of Lowenstine and Munson (1999), we investigated necropsy reports and liver tissue of 13 coatis from five zoological institutions. Two juvenile animals did not have abnormal iron deposits in the liver. One adult individual had only a few, four adult individuals had moderate, and six adult individuals had massive iron deposits in their liver tissue.
These results suggest that coatis could be considered among the species susceptible for excessive iron storage. Whether this problem represents a medical risk for the animals cannot be proven; however, in five cases the iron deposits were the major pathological finding. The fact that juvenile animals might be not affected agrees with the assumption of a diet-related problem, resulting from a chronic oversupplementation and accumulation. Captive coatis might benefit from diets that do not include substantial amounts of heme iron. Similar findings are to be expected in other omnivorous/insectivorous mammalian species that are kept on meat-based diets.
Lowenstine LJ, Munson L (1999) Iron overload in the animal kingdom. In: Fowler ME, Miller ER (eds) Zoo and Wild Animal Medicine. Current Therapy 4. W.B. Saunders Co., Philadelphia, 260-268
Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition
Effect of feed supplements on iron status in mynahsW. Arnhold1, R. Klieforth2, P. Morris2, M. Schröter3 D. Meissner3
1BASU-Minerals, Inc., Bad Sulza, Germany, 2Zoological Society of San Diego, San Diego, USA, 3Institute of Clinical Chemistry and Laboratory Diagnosis, Dresden, Germany,
Mynahs, toucans and birds of paradise which are kept in captivity are sensitive against Fe overload. It is assumed that nutritional factors play an important role for the development of hemosiderose in these species. There is the possibility that the diets contain less feed components that inhibit the Fe absorption compared to the feed in their natural habitat. Thats why two tests were carried out to investigate the Fe absorption inhibitory capacity of calcium carbonate and tamarind juice in mynahs.
Four breeding pairs of mynahs, which were kept in the San Diego Zoo Avian Reproduction Centre, were at our disposal. The birds received their normal diet. The diet of four mynahs was supplemented with calcium carbonate on six weeks (test 1) and with tamarind juice on eight weeks (test 2). The remaining four birds were used as control group. Quantitatively and qualitatively identical samples of the offered feed as well as feed residues and excrements were registered. Thus, it was possible to determine the consumption of the different kinds of feed as well as the Fe intake and the Fe digestion.
The Fe status was estimated by blood parameters like ferritin, transferrin, and hemoglobin.
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Iron Status in RuminantsW. Arnhold1,2, M. Anke2, M. Seifert2, S. Goebel3, B. Rideout4, M. Edwards4 G. Nötzold5
1BASU-Minerals, Inc., Bad Sulza, Germany, 2Friedrich Schiller University, Biological-Pharmaceutic Faculty, Institute for Nutrition and Environment, Jena, Germany, 3University Leipzig, Institute for Transfusional Medicine, Germany. 4Zoological Society of San Diego, USA. 5Zoological Garden Leipzig, Germany
The iron content of the various organ tissues in animals depends on nutrition, health status, age, and sex and varies among species. Although hemoglobin, serum ferritin and serum transferrin are influenced by parameters like health status, they are used for the assessment of an iron deficiency or overload in living animals. The iron storage of the body takes place in organ tissues with the highest iron concentrations i.e. liver, spleen, and bone marrow in which iron is bound as ferritin and hemosiderin. Whereas many results exist on the iron concentration in organ tissues of monogastric animals (Morris 1987) only a few datas are available in ruminants (GrÒn et al. 1980). Due to the species specifity of the iron status, organ tissues (liver, kidney, cerebrum, rib, skeletal muscle, heart, lung, aorta, spleen, and hair) of different wild ruminant species were analysed and compared with domestic ruminants.
The investigated wild ruminants which were kept in captivity came from the Zoological Society of San Diego and the Leipzig zoo. For comparison, organ tissues from wild living deer and domestic ruminants were obtained from different locations of Eastern Germany, and Northern California.
For the presentation of the results the various species of ruminants were classified as morphophysiological ruminant feeding types (Hofmann 2000).
The spleen accumulated the highest iron amounts per kg dry matter among the investigated organ tissues. The iron concentrations of cerebrum and ribs were the lowest.
There was a significant effect of the age on the iron status. In neonatals the liver and aorta contained two to three times more iron per kg dry matter compared to adults whereas the iron concentration of cerebrum was 1.5 times higher in neonatals than in adults. Spleen, lungs, kidney, and skeletal muscle of adult ruminants contain more iron with decreasing extent than neonatals. The iron concentration of heart muscle and rib did not differ between adult and neonatal ruminants.
Depending on organ tissue and age the iron concentration of the tissues differed between the ruminant feeding types, but not between male and female adult and neonatal ruminant feeding types.
99518 Bad Sulza
The next meal is today: feeding recommendations in the absence of scientifically sound results the question of iron availabilityM. Clauss1, J. Hummel1,2
1Institute of Physiology, Physiological Chemistry and Animal Nutrition, Munich, Germany
2Zoological Garden Cologne, Germany
Excessive iron storage is being recognized as a typical pattern found in man zoo animal species. Based on knowledge from human medicine, it is often presumed that the condition will have, in the long run, detrimental effects for the affected animals. Regardless of the cause of excessive iron absorption, it is reasonable again based on experiences from human therapy to assume that dietary prevention will help to delay or even alleviate the problem. Zoo nutritionists thus face the dilemma that conclusive results from studies with zoo animals are still largely lacking, but that on the other hand the next meal has to be formulated for today, with the well-being of the animal in mind.
In this contribution, we summarize existing knowledge on the prevention of high levels of (available) dietary iron, while at the same time explaining potential dangers associated with prevention measures. For example, iron content is generally very high in pelleted feeds for herbivores, but the exclusion of pelleted, formulated feeds from diets could result in deficiencies in protein, vitamins and other minerals. It is important not only to stress the negative high iron contents of certain feeds, but also to understand their positive and essential contributions to a diet, in order to chose the right dosage, or chose appropriate replacements.
In short, heme iron (from vertebrate meat) should be used sparingly in susceptible species. Complete pelleted feeds should be used with caution and their important ingredients (protein, other minerals and vitamins) could in certain cases be provided by other feeds, without seriously compromising practicality. Low-iron complete diets (such as for birds) could be tried for other species, and new low-iron products should be tested. Mineral supplements, particularly prone to have high iron contents, must be chosen with care. Vitamin C supplements should only be used in species with a proven requirement. Natural iron chelators, such as tannins from tea or tamarind, can be used with caution, but in the awareness that unknown side-effects might occur; their use should be no excuse for disregarding the iron content of other feed items. Until more is known about the mechanisms of excessive iron storage, monitoring measures (such as serum transferrin saturation testing) should be incorporated in the husbandry management of susceptible species.
Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition
Lemurs pumping iron.W. McCormick1,2, V. Melfi2 & C. Muller1
1 School of Biosciences, Cardiff University and 2 Paignton Zoo Environmental Park, Totnes Road, Paignton, Devon, TQ4 7EU
The provision of diets that meet the nutritional needs of captive primates is an essential part of preventative medicine and the promotion of good animal welfare. In recent years the incidence of iron storage disease (haemosiderosis) in lemurs has become a topical issue. Haemosiderosis occurs when the circulating level of iron in the blood becomes too high and so, it is stored in vital organs (e.g. liver) reducing their ability to function, in some cases with fatal consequences. Currently this condition can not be detected accurately with non-invasive methods.
A variety of explanations have been suggested to explain the incidence of haemosiderosis in zoo housed lemurs. The diet of wild and captive lemurs is thought to be different, in the levels of iron present (higher in captive diets) and the levels and types of tannins present (lower in captive diets). As such, it has been conjectured that captive lemurs will develop haemosiderosis because their intake of iron is too high, or because the level of tannin (which reduces the bodys absorption of iron) is too low. Despite the interest shown in this topic, empirical data is scarce (with the exception of a study by Wood et al., 2003).
This study aimed to generate empirical data that could investigate i) the relationship between iron levels in the diet fed and the iron excreted in faeces, ii) whether this relationship varied with different lemur species, and iii) possible relationships between iron and total phenolic intake. Data were collected from several institutions across the UK (ring-tailed N=4, red ruffed N=3, black and white ruffed N=3, red fronted N=3). An intake study was conducted to estimate the total amount of food consumed daily, for 5 days. This was repeated twice (total of 3 x 5 day). The total amount of faeces excreted was calculated for the corresponding days. A representative sample of each food type fed and of the faeces excreted were dried for each treatment (N=3). The iron content of the samples was measured using atomic adsorption spectroscopy, and the total phenolic content of the food was analysed using the Price-Butler method (1977).
Results demonstrated a significant contamination issue with regards to iron making intake-output comparison impossible as the lemurs appeared to be losing more iron than they were receiving in their diet. Soil was suggested as the possible contaminant, and consequently may impact on current husbandry techniques of haemosiderosis-prone species.
We are extremely grateful for the cooperation we have received, from other researchers, university supervisors (Laura Bellingham) and zoo managers (Stewart Muir, Paul Pearce-Kelly, Neil Bemment, Audrey Perkins), throughout this study. Samples analysed in this project were collected by Julie Mathews (Shaldon Wildlife Park, Shaldon, Devon), Clare Reed (Drusillas Park, East Sussex), Paula Walling (Drusillas Park, East Sussex) Jo Cook (London Zoo, London), Catherine Knight (Grangewood Safari Park, Derbyshire), and Shaun Bratchley (Grangewood Safari Park, Derbyshire).
Authors current address:
School of Bioscience
e-mai : Wanda.Mccormick@postgrad.manchester.ac.uk
Hepatic haemosiderosis in birds: nutritional composition and immune mechanisms may contribute to the development of the disease.G. Werquin
Versele-Laga, Deinze, Belgium
Heamosiderosis is a common finding in frugivorous birds kept in captivity. Until now, most pathologists consider a high iron content in the food as primary cause of this disease. Some researchers did formulate guidelines on maximum allowed iron levels, which are unfortunately not the result of nutritional research under controlled circumstances.
Also, these recommended dietary iron levels disregard the large differences in bio-availibility of the iron present in the food. Iron bio-availability is determined by several factors:
1. Sources of dietary iron: Dietary iron is available in two valence states, Fe2+ (ferrous) and Fe3+ (ferric). The majority of ferrous iron is found in haem iron and the majority of ferric iron is found in non-haem iron.
Haem iron is present in the haemoglobin and myoglobin in animal products. This form of iron is relatively available: about 30% of haem iron is absorbed from the diet. The level of haem iron absorption is relatively unaffected by other dietary factors.
Non-haem iron is found in plant foods such as cereals, vegetables, pulses, dried fruit, etc and compared to haem iron it is relatively poorly absorbed, typically less than 10% and often under 5%. The absorption of non-haem iron is much more influenced by the iron status of the animal and several factors in the diet that can either inhibit or enhance its absorption.
2. Factors influencing the dietary non-haem iron absorption:
The presence of iron chelating agents in the food may reduce the bio-availability of non-haem iron. Tannins reduce the absorption of non-haem iron due to the formation of insoluble iron tannate complexes. Phytate found in the bran of wheat and other cereals strongly inhibits non-haem iron absorption by interacting with it, rendering it less soluble. Oxalates in green leafy vegetables bind iron, preventing absorption. Also calcium and soil clay interfere with iron absorption.
Vitamin C, organic acids or a low dietary pH enhance iron absorption by reducing the ferric iron to the more readily absorbed ferrous form.
The evaluation of the dietary iron load should not be limited to the iron content of the food ration, but should also attempt to take all other important dietary factors into consideration. Due to the wide variation of energy density in bird foods, recommendations on dietary iron levels should be set on energy basis rather than on weight basis.
Besides dietary factors, also other mechanisms may play an important role in the pathogenesis of haemosiderosis. As in mammals, also in birds, withholding iron from potential pathogens has been described as a host defense strategy. In mammals, blood iron is regulated by 2 proteins : lactoferrin and transferrin. Both proteins have a high affinity for iron and are bacteriostatic in vitro for a number of bacteria. In birds, blood iron is regulated by transferrin only. During stress or infections, transferrin is released in birds, which binds the blood iron but also increases intestinal iron absorption and iron flux to the liver. This mechanism may be as important as the dietary iron load in the pathogenesis of haemosiderosis.
Poster: Sources of high iron content in manufactured pelleted feeds: a case reportM. Clauss1, J. Hummel1,2, P. Eloff3, R. Willats3
1Institute of Physiology, Physiological Chemistry and Animal Nutrition, Munich, Germany, 2Zoological Garden Cologne, Germany, 3Wes Enterprises, Thabazimbi, Republic of South Africa
The analyzed values for iron contents of pelleted feeds are often surprisingly high, exceeding the content calculated on the basis of the assumed iron content of the individual ingredients. A common question asked is how such high iron levels in pelleted feeds can be avoided. In order to investigate potential sources of iron in a pelleted mixed feed, we sampled raw ingredients, processed ingredients, processed mixtures and the final product of Boskos® game pellets. Boskos® game pellets consist of South African browse plants, mainly acacias, harvested during field operations against bush encroachment, of lucerne, various sources of proteins and carbohydrates, and two mineral/vitamin premixes. Representative samples were taken from the production process, and analyzed for iron content.
Two major sources of iron in the final product could be identified. Iron content was low in lucerne and very low in South African bush (app. 40 mg/kg dry matter), but increased after mechanical processing (drying/milling). The iron content of the complete food mixture was reduced after it passed a magnet which is a routine instalment in food manufacturing plants. This indicates that metallic abrasion during mechanical processing can be one cause of increased iron content in manufactured feed. The other organic ingredients had various iron contents. However, iron content was extremely high in the two mineral/vitamin premixes used (5000-7000 mg/kg dry matter), for which the iron content was not specified by their respective providers. These results indicate that, if iron content is an issue of concern, mineral additions must be chosen with particular care in order to avoid unnecessary iron contamination.
The iron content of the final product was within the range analyzed in other pelleted animal feeds (400-500 mg/kg dry matter). Such products are unlikely to be harmful for species not susceptible to iron storage disease, such as ruminants, white rhinos etc. Species susceptible to iron storage disease, in contrast, such as black rhinos, should probably not receive such feeds on a regular basis; if at all, such products can be used in these species for short time periods, such as transport/translocation, where the direct acceptance of the product is more important than potential long-term effects. Wes Enterprises is currently testing different mineral/vitamin supplements for the production of an iron-controlled version of Boskos®.
Institute of Animal Physiology, Physiological Chemistry and Animal Nutrition