Exogenous corticosterone mimics a late fasting stage in captive Adelie penguins (Pygoscelis adeliae).

• Published in: American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
• Main Authors: Spee, Marion, Marchal, Lorène, Thierry, Anne-Mathilde, Chastel, Olivier, Enstipp, Manfred, Le Maho, Yvon, Beaulieu, Michaël, Raclot, Thierry
• Other Authors: Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé (CEBC), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDE]Environmental Sciences; Pygoscelis adeliae
• Online Access: https://hal.science/hal-00573256; https://doi.org/10.1152/ajpregu.00762.2010

International audience Fasting is part of penguin's breeding constraints. During prolonged fasting three metabolic phases occur successively. Below a threshold in body reserves, birds enter phase III (PIII), which is characterized by hormonal and metabolic shifts. These changes are concomitant with egg abandonment in the wild and increased locomotor activity in captivity. Because CORT enhances foraging activity, we investigated the variations of endogenous CORT, and the effects of exogenous CORT on the behavioral, hormonal, and metabolic responses of failed breeder Adélie penguins. Untreated and treated captive male were regularly weighed and sampled for blood while fasting, and locomotor activity was recorded daily. Treated birds were implanted with various doses of CORT during phase II. Untreated penguins entering PIII had increased CORT (3.5-fold) and uric acid (4-fold; reflecting protein catabolism) levels, concomitantly with a rise in locomotor activity (2-fold), while prolactin (involved in parental care in birds) levels declined by 33 %. In CORT-treated birds, an inverted-U relationship was obtained between CORT levels and locomotor activity. The greatest increase in locomotor activity was observed in birds implanted with a high dose of CORT (C100), locomotor activity showing a 2.5-fold increase, four days after implantation to a level similar to that of birds in PIII. Moreover, uric acid levels increased 3-fold in C100-birds, while prolactin levels declined by 30 %. The experimentally-induced rise in CORT levels mimicked metabolic, hormonal, and behavioral changes characterizing late fasting, thus supporting a role for this hormone in the enhanced drive for refeeding occurring in long-term fasting birds.