Comparison of blood antioxidant responses among Catharacta maccormicki (South Polar Skuas) and Catharacta antarctica lonnbergi (Brown skua)

ANSALDO, MARTÍN; REPETTO, MARISA; MONTALDI, DANIEL

Berichte zur Polar und Meeresforschung

Helmholtz- Gemeinschaft

Lugar: Bremerhaven; Año: 2005 vol. 507 p. 113 - 116

1618-3193

Brown and South Polar skuas nest sympatrically in a few areas, mostly along the Antarctic Peninsula between 61° and 65°S. At these sites there appears to be a sharp partitioning of food resources; Brown skuas monopolize the terrestrial food source of penguin eggs and chicks, and South Polar skuas forage almost exclusively at sea. Skuas, like other Antarctic organisms, are exposed to severe environmental conditions such as extremely low temperature and high UV radiation levels, that exert oxidative stress. The aim of this work was to investigate the possible effects of different sources of food on antioxidant responses in blood samples of both species of skuas at two different stage of life. Sample were collected from adults and chicks of skuas, nesting on Potter Peninsula (King George Island, South Shetland Islands, Antarctica), during the breeding season of 1999-2000. total of 33 skuas were studied, 18 of which were South Polar skua, Catharacta maccormicki (6 adults and 12 chicks), and 15 brown skua, Catharacta antarctica lönnbergi (7 adults and 8 chicks). Approximately 5 mL of blood were drawn from the brachial vein of the seabirds using an heparinized 22 gauge needle. Whole-blood samples were centrifuged for 15 min at 3000 rpm. Red blood cells and plasma were separated and immediately frozen at ?20 Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities as total glutathione, total antioxidant capacity (TRAP) and total antioxidant reactivity (TAR) were measured. Antioxidant enzyme activities in blood of chicks and adults skuas. Data are expressed as mean values ± SEM. Number of animals between brackets. Multiple comparisons among species and stages: values followed by different letters are significantly different at p< 0.001.