Erythrocytes nuclear abnormalities and leukocyte profile of the immune system of Adélie penguins (Pygoscelis adeliae) breeding at Edmonson Point, Ross Sea, Antarctica

Antarctic seabirds well adapted to extreme environments often deal during their life cycle with sub-optimal conditions and occasionally with severe environmental stress. Climate changes, pollution, habitat loss, increasing human presence can all significantly affect organism's health status from molecular to individual up to population level. In the present study, erythrocyte nuclear abnormalities (ENAs) and white blood cells (WBCs) differential were investigated in 19 adults of Adelie penguin (Pygoscelisadeliae) breeding at Edmonson Point, Antarctic Specially Protected Area (ASPA n. 165) in the Ross Sea. Micronuclei (MN) accounted for 10.50% of observed abnormalities in penguin erythrocytes while kidney-shaped nucleus (KSN) was the most abundant (20.88%). Heterophils (HE) were the most common WBC (36.93%) in agreement with the generic avian leukocytes profile while eosinophils (EO) were the lowest (7.45%). A low number of lymphocytes were detected resulting in a higher heterophils to lymphocytes ratio. ENAs and H:L ratio are confirmed as reliable indexes of penguin's health status since they reflect their individual adaptation during breeding season. These baseline data will be useful for future studies as indicators of penguin's health status mainly as response to environmental changes.