Avian nutrition

Using mortality and reproduction data to evaluate captive penguin nutrition

R. Pizzi1,2, M. Gibbons2, A.M. Wood 3, G. Mackenzie3, M.C. Garcia-Rueda3

1Royal Zoological Society of Scotland, Edinburgh Zoo, UK, 2Royal (Dick) School of Veterinary Studies, Edinburgh University, UK, 3Veterinary laboratories Agency (VLA), Lasswade, UK

While evaluating diets fed to penguins in captivity with that consumed by wild birds would be ideal, there is a paucity of much relevant knowledge. Little nutritional analysis of Notothenioid fish species has been performed. The small amount of lipid and vitamin analysis in Antarctic krill Euphausia superba, the predominant prey of numerous penguin species, has shown marked variation in nutritional content, dependant on season, gender, and life stage of krill. It is also known that some penguin species can discriminate and actively consume gravid female krill, further complicating extrapolation to captive diets. Instead a combination of needs extrapolated from domestic poultry, other fish eating vertebrates, and partial knowledge of wild diets has previously been used. Penguins have been kept for over a hundred years in Edinburgh zoo. A large closed population of King penguins Aptenodytes patagonicus, Gentoo penguins Pygoscelis papua, Macaroni penguins Eudyptes chrysolophus, and Rockhopper penguins Eudyptes chrysome, has been maintained for the last 40 years. This appears to be the largest long-term self-sustaining captive penguin population in the world, and offers a unique opportunity for nutritional research. Of the more than 1200 penguin post-mortem examinations performed at Edinburgh zoo, 813 post-mortem examinations have been performed in the last 40 years, 635 of which are of a single species, the Gentoo penguin Pygoscelis papua. Analysis of mortality and disease incidence patterns, as well as reproductive success have been correlated with dietary changes, as a different method of trying to determine the impact of captive nutrition. The adult gentoo penguin population has shown a significant rise (p<0.01) in mortality rate between 1964-2003 (95%CI of gradient: 0.12-0.51). The median age at death of adult gentoo penguins has fallen from 8 years (95%CI 7-10, n=199) during the period 1980-1990 to 5 years (95%CI 3-8, n=118) during the period 1993-2003. Interesting findings, confounding factors, and limitations will be discussed.

Author’s address:
R. Pizzi
Royal Zoological Society of Scotland Edinburgh Zoo/
Dept of Veterinary Clinical Studies
Royal (Dick) School of Veterinary Studies
Edinburgh University, Easterbush, Roslin
Midlothian, EH25 9RG,
United Kingdom
e-mail romain.pizzi@ed.ac.uk

Novel plumage pigments, novel prey species antioxidants and immunostimulants: implications for captive penguin nutrition.

R. Pizzi1,2 , K.J. McGraw3, P.M. Nolan3, M. Gibbons1

1Royal Zoological Society of Scotland, Edinburgh Zoo, UK, 2Royal (Dick) School of Veterinary Studies, Edinburgh University, UK, 3Arizona State University, Tempe, AZ, USA

Gentoo penguins (Pygoscelis papua) fed a captive diet deficient in astaxanthin, the carotenoid present in their main prey, Antarctic krill (Euphausia superba), appear to develop pale beaks and feet, in contrast to the bright orange coloration seen in wild birds. King, macaroni, and rockhopper penguins kept under the same conditions and fed a similar diet in captivity do not show any change in coloration. Recent work has shown yellow plumage coloration in macaroni penguins (Eudyptes chrysolophus), king penguins (Aptenodytes patagonicus) and emperor penguins (Aptenodytes forsteri) is not due to carotenoids, but possibly to pterins, a novel group of pigments not described before in the plumage of other avian species. These pigments are soluble in mild acids and bases and fluoresce strongly under UV light, characteristics consistent with pterins, only previously isolated from the yellow, orange, and red irises of blackbirds, starlings, owls, pigeons, and the wings of some Lepidoptera. Yellow plumage patches have been shown to affect mate selection in the wild in species such as the king penguin. Zoo visitors may also notice the abnormal appearance of paler birds.

Work on Notothenioid fish species and Euphausia superba krill has shown that aside from α-tocopherol (Vitamin E), these penguin prey species contain Marine Derived Tocopherol (MDT), α-tocomonoenol, postulated to enhance antioxidant activity at low temperatures. Notothenioid fish have higher levels than phytoplankton, showing accumulation in the food chain. The situation is unknown in sub-antarctic seabirds, but potentially may be similar. Piscivorous birds such as penguins probably have higher antioxidant requirements than other avian species due to their high intake of polyunsaturated fatty acids. Freezing, storage and thawing of fish is also likely to deplete antioxidant content, increasing supplementation levels needed. Pacific krill (Euphausia pacifica) has not been shown to contain MDT. It is used in calculating wild penguin diets in lieu of antarctic krill as there is more published literature on its nutritional content. This practice may be questionable. Until further research has elucidated the situation regarding carotenoids and MDF in wild penguins, it may be prudent to include or supplement α-tocopherol (Vitamin E) at a higher level in the captive diet than is known to occur naturally in wild penguin prey.
Antarctic krill extracts are currently being researched for a variety of reported beneficial effects. Chickens fed a commercial broiler diet containing 0.5% krill chitin, have shown significant weight gains and increased feed efficiency, compared to controls. These are believed to be due to a change in intestinal microflora. Chitosan, a deacetylated form of chitin polysaccharide polymers found in the exoskeleton of Antarctic krill, has been demonstrated to act as an immunostimulant in salmon and trout. It has also been shown to have beneficial effects in the management of chronic renal disease and hypercholesterolaemia in humans. The ability of the penguin digestive system to deacetylate chitan polysaccharide is not known. Despite the beneficial effects of chitosan, it can also very significantly reduce the absorption of lipid soluble vitamins A, D, E and K, as well as carotenoids, and therefore its use as a supplement does not seem wise. It remains to be seen whether inclusion of fresh-frozen Antarctic krill in captive penguin diets would be beneficial, or justify the associated costs.

Author’s address:
R. Pizzi
Royal Zoological Society of Scotland Edinburgh Zoo/
Dept of Veterinary Clinical Studies
(Dick) School of Veterinary Studies
Edinburgh University, Easterbush, Roslin
Midlothian, EH25 9RG,
United Kingdom
e-mail romain.pizzi@ed.ac.uk

Nutrient composition of the diet of captive and wild kiwi (Apteryx mantelli) in New Zealand

Wouter Hendriks1, Murray Potter2 and Nicola Pindur2

1Institute of Food, Nutrition and Human Health, 2Institute of Natural Resources, Massey University, Palmerston North, New Zealand.

Diets fed to kiwi (Apteryx mantelli) held in captivity in New Zealand are based loosely on a recipe recommended in the kiwi husbandry manual that was formulated over 30 years ago (Reid, 1970). Adult kiwi in captivity have been found to suffer higher mortality and lower fertility rates, and produce smaller eggs with lower hatchability and thinner egg shells compared to adults in the wild. Surprisingly, the diet of the North Island brown kiwi held in captivity has never been formulated on nutritional information from the natural diet of wild kiwi, nor has the nutritional composition of the current formulations been determined. The aim of the studies reported here was to compare nutrient composition of diets fed to captive kiwi to that of the diet of kiwi in the wild in order to improve the formulations.
Diets from seven institutions holding kiwi were analysed for dry matter, ash, crude protein, crude fat, amino acid and fatty acids. Data on the composition (dry matter, ash, amino acids and fatty acids) of the diet of kiwi in the wild were obtained from analysis of the gizzard content of wild kiwi carcasses.
Large differences were detected in the type and quantity of ingredients used to formulate the kiwi diets by each institution. A total of 19 different ingredients were used with the number of ingredients used in each formulation varying from 3-10. The main ingredients used were oxheart, cat biscuits and roll oats. All of the diets were formulated using meat as the main ingredient with three using a combination of meat and cat biscuits. Chemical analysis of the seven diets showed a large variation in nutrient content with organic matter ranging from 89.6 to 96.9%, crude protein from 23.0 to 42.7% and crude fat from 5.4 to 24.4% of the dry matter. The mean organic matter content of the gizzard content of the wild kiwi was 72.1% with a range of 49.9 to 93.0 %. The protein content varied from 18.4 to 51.0% with a mean of 31.4%. The total fatty acid content was highly variable with a range of 0.4 to 3.9% and a mean value of 1.96%.
Each captive institution in New Zealand appears to have their own recipe for a kiwi diet with overall 19 different ingredients being use with almost all being foreign to kiwi with the exception of an insectivore mixture. Kiwi in the wild have been reported to predominantly consume insects, invertebrates and plants. The nutrient composition of the captive diets varied greatly in crude protein, fat and carbohydrates. Comparison of the nutrient composition of these diets with the gizzard content of kiwi shows that the current diets are high in organic matter and fatty acids. Especially the latter is approximately 5.8 times higher in the captive diets compared to that of the gizzard content. In addition, the carbohydrate content of the captive diets is predominantly starch (derived from cat biscuits, oats, tofu and wheat germ), the intake of which is almost certainly low in wild kiwi.

Reid, B. 1970: Feeding kiwis in captivity. Wildlife - a review 2 26-30.
Author’s address:
W.H. Hendriks
Institute of Food, Nutrition and Human health
Massay University
Palmerston North
New Zealand
e-mail W.Hendriks@massey.ac.nz

Long-term effect of dilution degree of nectar food and the feeding of pollen on the condition of nectarivorous parrots at Loro Parque Fundacion.

G.P.J. Janssens1, B. Geeroms1, M. Burkle2, L. Crosta2, M. Reinschmidt2, G. Werquin3

1Laboratorium of Animal Nutrition, Ghent University, Belgium, 2Loro Parque Foundation, Puerto De La Cruz, Tenerife, Spain ,3Versele-Laga Ltd., Deinze, Belgium

Nectarivorous parrots in captivity are commonly fed a commercial nectar food. Nectar foods are sold as a powder that has to be diluted in order to become a nectar-like solution.
A previous study (Janssens et al., 2003) demonstrated that the dilution level had a significant impact on the voluntary energy intake of two rainbow lorikeets subspecies. Due to the short-term character of that trial, only limited changes in body weight and body condition were observed. Besides nectar, pollen are also considered as a main ingredient in the diet of nectarivorous parrots (Cannon, 1984). Only scarce information is available on the feeding value of pollen and its dietary necessity for nectarivorous parrots (Frankel and Avram, 2001).
The present study aimed to clarify whether the dilution degree of nectar food and the feeding of pollen could affect body weight and body condition in a large population of nectarivorous parrots at longer term.
Nectarivorous parrots in the collection at Loro Parque Fundacion were randomly allotted to four dietary treatments: Two groups (D3_0 and D3_P) were fed a commercial nectar food (Nutribird Lori, Versele-Laga, Deinze, Belgium) at a dilution in water of 1/3 (v/w), whereas the other two groups (D4_0 and D4_P) were fed a dilution in water of 1/4 (v/w). Groups D3_P and D4_P also received pollen (mixed flower pollen, Pollenergie, France) in their diet at an inclusion rate of 1/5 (w:w on undiluted nectar food basis). Fresh pollen were nitrogen-packed and frozen.
Pairs without chicks were also given fruit and mealworms in the afternoon.
At day 0 and day 100, all birds were clinically examinated and weighed. A body condition score was given, with 1 = underweight, 3 = normal and 5 = obese. This was done by checking the pectoral covering over the sternum and the fat deposits around the cloaca.
The difference in weight change was not significant between groups. Yet, the change in body condition score was significantly affected by the dilution degree of the nectar food (p=0.005).
Differences between genders and the feeding of pollen did not reach the level of significance (p>0.05). Body condition scores increased with body weight, and were significantly different between species. Whether this can be contributed to biased condition scoring or to the elevated risk of large species to become obese, should be further investigated.
Breeding results were numerically better in the pollen-fed birds, but statistical analysis was not possible.
An appropriate dilution degree of nectar food might be a useful tool to prevent aberrant body condition like obesity in nectarivorous parrots.
· Cannon, C.E., 1984. The diet of Trichoglossus spp. In the Queensland-New South Wales border region. Emu 84, 16-22.
· Frankel, T.L., Avram, D., 2001. Protein requirements of rainbow lorikeets, Trichoglossus haematodus. Australian Journal of Zoology 49, 435-443.
· Janssens, G.P.J., van Loon, M., Burkle, M., Crosta, L., Reinschmidt, M, Werquin, G., 2003. Influence of dilution level of nectar feed and fruit offer in two subspecies of rainbow lorikeets. Proceedings of the 7th Conference of the ESVCN, October 3-4, 2003, Hannover, Germany, p.69.

Author’s address:
G.P.J. Janssens
Laboratorium of Animal Nutrition
Ghent Universtiteit
Heidestraat 19
B-9820 Merelbeke
e-mail geert.janssens@ugent.be

Investigations of dietary calcium requirements in growing storks

A.L. Fidgett1 and E.S. Dierenfeld2
1North of England Zoological Society, Chester Zoo, United Kingdom; 2Saint Louis Zoo, MO 63110, USA
Storks are semi-aquatic carnivorous birds that have historically not bred well in captivity; nutritional factors may well underlie health and successful reproduction in these altricial, rapidly growing species. Although rather catholic in choice of food items in nature much of the year, following hatching, storks have been anecdotally reported to feed frogs almost exclusively to growing chicks. Whole frogs analysed contain up to 5% calcium (DM basis). Field data may thus provide a clue to calcium (and other nutrient) requirements of growing storks. To date, there are few investigations that quantify nutrient needs of altricial avian species. We hypothesize: 1) calcium needs of altricial chicks are higher than those of precocial species, thus poultry do not provide an appropriate physiological model – although a combination of domestic carnivore and poultry data may; 2) growth rates and deposition of calcium are higher in altricial, long-legged bird species compared with poultry species, and 3) prey consumed by storks in nature varies in calcium content on a seasonal basis, corresponding with the nutrient needs of growing chicks. This study attempted to evaluate calcium nutrition of storks by evaluating data both indirectly via the literature and directly within zoos using growth and diet records from captive storks.

Author’s address:
A.L. Fidgett
North of England Zoological Society
Chester Zoo, Chester
Cheshire, CH2 1LH
United Kingdom
e-mail a.fidgett@chesterzoo.org

Nutritional management and feeding behavior during hand- and parent- rearing of Great grey shrikes (Lanius excubitor meridionalis) chicks in captivity and in the wild.

Helena Marqués1, Albert Porté2, Anna Vives2, Noé Torrent2 and Damià Sánchez2

1Conzoolting Wildlife Management s.l. Serra del Montsant 6, Barcelona, Spain., 2Associació Trenca, Centre de Fauna de Vallcalent, Lleida, Spain.

The situation of the Lesser grey shrike (Lanius minor) in the Iberian Peninsula during the last few years suggests that conservation strategies should be taken. The Departamento de Medio Ambiente (Generalitat de Catalunya), the Trenca Association and the Spanish Ministerio de Medio Ambiente are developing an Experimental Captive Breeding Plan for the Lesser grey shrike. Its aims are to contribute to the future reinforcement of the wild populations through captive propagation, and to develop an education program to sensitize the public. The Experimental Captive Breeding Plan is being developed using a surrogate species, the Great Grey Shrike (Lanius excubitor meridionalis). The nutritional program is one of the key factors for a successful captive breeding. Additionally, observations of the feeding behavior during parent chick-rearing both in captivity and in the wild are also important considerations to take into account.
In the spring of 2003 twelve eggs of the Great grey shrike, were taken from the wild to develop working protocols such as the chick hand-rearing feeding protocol. Six growing diets were formulated using a variety of ingredients and proportions that changed according to the age and requirements established for the chicks. The amount of food was offered as a percentage of body weight, starting at 25% and increased progressively until 50%. From day 30 of age onwards, a meat-ball diet was formulated and offered alternatively with life insects during the week. During the first month chicks were weighed daily and the diet consumed by each chick was registered. Eighty three percent of the chicks hand-reared from day 1 reached adulthood without any clinically apparent health problem. The survival rate and average daily weight gain of the chicks were very similar to those observed by the San Diego team working with L. ludovicianus mearnsi.
In spring of 2004, 13 chicks of the same species between 5-8 days old were taken from three wild nests. The aim was to test the 2003 protocols and adapt them to the new situation. It has been documented that hand-rearing one-week old chicks is much more successful and less demanding than rearing chick from day 0. Chicks caught from the wild, weighed two times more than the same age chicks hand-reared from day 0. The same diet protocol as in 2003 was used, but a few adaptations were made. Chicks from both experiences reached adult weight (57 g average) in the same number of days (27). In this second experience, all the chicks reached adulthood without any apparent health problem.
At the beginning of March of 2004, the 2003 hand-reared chicks were paired, and two of the pairs bred (one of them twice). The complete development of the parent reared chicks was recorded with a camera allocated on top of the nest. Although chicks were not weighed to avoid interfering too aggressively with the animals, some chick rearing behaviors could be registered, like number of times the chicks were fed by adults and several observations of the type of ingredients the adults provided to the chicks were also recorded. These results could be compared with the results obtained by recorded images taken from wild nests of both L. excubitor and L. minor.

The feeding protocol used to hand-rear L. excubitor may be applicable to hand-rear L. minor since both species are biologically very similar.

Authors address:
H. Marqués
Conzoolting Wildlife Management s.l. Serra del Montsant 6,
08415 Bigues i Riells
E-mail: nutricion@conzoolting.com,

Circulating concentrations of vitamins A and E in avian species; evidence for dietary relationships?

A.L. Fidgett1 and E.S. Dierenfeld2

1North of England Zoological Society, Chester Zoo, United Kingdom; 2Saint Louis Zoo, USA

Our understanding of vitamin requirements and interrelationships within the class Aves is based almost entirely on a single species, the chicken Gallus gallus. Being granivorous, the chicken has a fairly restricted feeding niche. Thus, vitamin nutrition of birds with diverse nutritional strategies beyond this food group remains poorly understood. Only a small proportion of vitamin requirements can be met by endogenous synthesis in birds; most needs must be met by their diet. Beyond the symptoms of severe deficiencies, little is known about the vitamin requirements of nondomestic species although distribution of vitamins in foods is a major factor determining the probability of deficiencies. Fat-soluble vitamins are usually found in the diet in association with lipids necessary for their absorption and transportation, vitamin A being most prevalent in foods of animal origin and vitamin E more concentrated in plant material. As part of routine testing, blood samples representing 169 species from 19 orders were collected and analysed for a-tocopherol and retinol concentrations; diet diversity was also scored for each species using data collated from natural history literature and published research. We report summary survey values for circulating concentrations of vitamins A and E in these avian species that may be useful guidelines for clinical assessment of nutritional status and also appear to be correlated with feeding niche.

Author’s address:
A.L. Fidgett
North of England Zoological Society
Chester Zoo, Chester
Cheshire, CH2 1LH
United Kingdom
e-mail a.fidgett@chesterzoo.org

Influence of a seed diet versus a formulated diet on bodyweight and intestinal flora in budgerigars (Melopsittacus undulatus) over a six-month observation period

J.M. Hatt1, P. Keller2, I. Fischer1

1Division of Zoo Animals and Exotic Pets, Department of Small Animals, University of Zurich, Switzerland , 2Division of Animal Housing and Welfare, Switzerland

Two groups, including 22 randomly selected 2-year-old budgerigars (Melopsittacus undulatus) each, were housed under identical conditions for 6 months, with the diet being the only difference. One group was offered a commercial seed mixture ad libitum plus carrots (0.5 g FM/bird/d) and a mineral supplement. The other group received a commercial formulated diet (4g FM/bird/d, manufacturer recommendation) for budgerigars plus carrots (0.5 g FM/bird/d).

Table 1. Analysis of a diets fed to budgerigars (Melopsittacus undulatus).
Values are expressed on a fresh matter (FM) or dry matter (DM) basis.

Unit Pelleted diet Seed diet (dehulled)
Water g/kg FM 77.4 100.6
Crude ash g/kg Dm 36.5 32.6
Crude protein g/kg Dm 171 171
Crude fibre g/kg Dm 21.0 29.5
Crude fat g/kg Dm 96 75
Acid detergent fibre g/kg Dm 48 -
Neutral detergent fibre g/kg Dm 88 -
Metabolizable Energy MJ/kg Dm 19.3 17.0
Calcium g/kg Dm 4.1 0.4
Phosphorus g/kg Dm 4.3 5.0
Sodium g/kg Dm 0.6 0.8

On day 0, 15, 20, 37, 92, and 189 each animal was weighed. The average bodyweight of the pellet-diet group dropped after diet-changing to a minimum average of 41.5g (i.e. a decrease of 16%) on day 15 compared to day 0. One bird died on day 16 due to emaciation. Following an increase of the formulated diet of 50% bodyweights increased by day 37 to 48.1g. At day 92 the average bodyweight (44.9g) dropped again (9.9%) compared to day 0 and subsequently increased again by day 189 (49.7g) without change to the diet.

Average bodyweight of the seed-diet budgerigars remained constant during the trial.
On day 92, and 189 faeces of each animal were analysed microscopically with Gram stain. The evaluation of the faecal samples revealed no significant differences between both groups, with the exception of Macrorhabdus ornithogaster which was found in 7.7% of samples of seed diet group versus 36.6% in the formulated diet group. Gram-positive rods dominated (79.1%) over Gram-positive cocci (14.7%). Gram-negative rods were found in 25.6% of the samples. No yeasts were diagnosed.

The present study shows that transition of seed fed budgerigars to a formulated diet is possible, but that bodyweights should be carefully monitored during transition and amounts fed to birds may have to be higher during transition than for subsequent maintenance. A possible explanation for the decrease in bodyweight at day 92 in the formulated diet group could not be found.
The observation that the formulated diet did not have a significant effect on intestinal flora differs from another study in 100 African grey parrots (Psittacus erithacus). Possible reasons may be that the durations of both studies were not comparable or that the different number of animals had an influence on the interpretation. Additionally it may be that the diets used in the two studies or the species may be too different to allow comparison.

A possible reason for the increased occurrence of Macrorhabdus ornithogaster may be the stress of transition to the formulated diet.

Author’s address:
J.M. Hatt
Division of Zoo Animals and Exotic Pets
Department of Small Animals
Vetsuisse Faculty University of Zurich
Winterthurerstrasse 260
8057 Zurich
e-mail jmhatt@vetclinics.unizh.ch