Plasma corticosterone level and protein electrophoresis in Antarctic Brown Skua (Stercorarius antarcticus): Effects of breeding

IBÁÑEZ, A.E.; GRAÑA GRILLI, M.; FIGUEROA, A.; PARI, M.; MONTALTI, D.

Chascomús

Jornada; XVI REUNIÓN DE LA SOCIEDAD ARGENTINA DE BIOLOGÍA; 2014

During the reproductive cycle, seabirds have to cope with different energetic stress situations, and corticosterone secretion is one of the physiological means through which homeostasis is maintained. To understand better the relationship between corticosterone level and body condition we studied the hormonal behavior and plasma protein profile of the antarctic Brown Skua during breeding season. Blood samples were obtained in three different moments: In (incubation), Pi (after egg hatching) and Pii (during chick rearing). Plasma corticosterone was assessed by radioimmunoassay. Also, protein agarose electrophoresis was performed to assess nutritional and immune condition by analyzing albumin, α1, α2, β and γ globulins concentration. A rise in corticosterone level was observed during the In period. In addition, a significant decrease in total protein and in albumin, β- and γ- globulin fractions were observed in the course of different periods, indicating that mobilization of energy stores via protein catabolism and immunological consequences occurred during breeding. Finally, the decline in body condition in adults during incubation together with the high levels of corticosterone describe the adaptability of skuas during periods of high energy demand.