Abstract
In 2010, the IUCN reclassified the threat status of the African penguin (Spheniscus demersus) from Vulnerable to Endangered due to declines in Western breeding populations in South Africa thought to be the result of the disappearance of their primary prey items (sardine and anchovy). With this recent reclassification the management of groups of African penguins under human care becomes increasingly important to ensure propagation and survival of this species. Proper nutrition is the cornerstone of good health and a critical determinant in the successful conservation and propagation of captive and free-ranging penguin populations. Dietary nutrient concentrations have been shown to be of particular importance to the molt and reproductive success of other species of penguins in captivity.1-3 Little is known about the trace mineral and vitamin requirements of penguins and requirements for diet formulation are often based on those determined for domestic animals. The goal of this study is to better understand the nutritional requirements of African penguins by developing baseline nutritional markers in penguins managed in aquaria and comparing values to healthy and nutritionally compromised wild penguins from South African populations. Blood samples were collected from penguins managed at two different aquariums (N = 65) and from healthy free-ranging birds from both Eastern (N = 20) and Western Cape (N = 20) populations during penguin colony health assessments in South Africa. In addition, blood samples were collected from nutritionally compromised birds (N = 20) that are admitted to the SANCCOB rehabilitation facility. Trace minerals (cobalt, copper, iron, manganese, molybdenum, selenium, and zinc), vitamins (A, E), and heavy metals (arsenic, lead, mercury, cadmium, thallium) were analyzed at Michigan State University. Preliminary results from aquarium managed birds suggest consistency in trace mineral levels in penguin collections between institutions and within a collection sampled over multiple years. Vitamin levels, however, were highly variable and likely were reflective of dietary, molting, and/or reproductive state of the birds. Strong correlations were noted between mercury and selenium, suggesting that selenium may exert a protective role when mercury levels are high, as seen in other seabirds and marine mammals.4 Results from the samples collected in South Africa are still pending.
Acknowledgements
The authors wish to thank staff, volunteer, and veterinary teams at each participating institution for assistance in penguin handling, blood collection and sample processing. Financial support for this project was provided by Georgia Aquarium.
* Presenting author
Literature Cited
1. Crissey SD, McGill P, Simeone AM. Influence of dietary vitamins A and E on serum α- and γ-tocopherols, retinol, retinyl palmitate and carotenoid concentrations in Humboldt penguins (Spheniscus humboldti). Comp Biochem Physiol A. 1998;121:333–339.
2. Monroe A. Annual variations in plasma retinol and alpha-tocopherol levels in gentoo and rockhopper penguins. Zoo Biol. 1993;12:453–458.
3. Ghebremeskel K, Williams TD, Williams G, Gardner DA, Crawford MA. Dynamics of plasma nutrients and metabolites in moulting macaroni (Eudyptes chrysolophus) and gentoo (Pygoscelis papua) penguins. Comp Biochem Physiol A. 1992;101:301–307.
4. Woshner V, Knott KK, Wells RS, Willetto C, Swor R, O'Hara T. Mercury and selenium in blood and epidermis of bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, FL: interaction and relevance to life history and hematologic parameters. EcoHealth. 2008;5:360–370.