Phenotypic plasticity in Pygoscelis adeliae physiology and immunity under anthropogenic pressure: a proteomic and biochemical scenario

The capacity of seabirds to shape their physiological and immune phenotypes may often be constrained by the ecological context. While phenotypic plasticity in physiological traits has been previously studied, the molecular mechanisms underlying phenotype plasticity in response to environmental stress have been little explored. This prompted us to enquire about how the nutritional and immune status are involved in physiological adaptations in breeding seabirds under anthropogenic pressure. At Esperanza (Hope) Bay, Antarctic Peninsula exists one of the biggest breeding penguin colony of Pygoscelis adeliae (Adélie). At this location, penguins nest nearby the Argentinian Esperanza Station and, therefore, are exposed to high levels of disturbance, whereas there is a low disturbed area, where penguins also breed far away from the Station. In both areas, the nutritional and immune status in breeding individuals was addressed and serum protein expression level was analyzed using a proteomic approach. Body mass, proteins, albumin, and triacylglycerol were higher in penguins from the low disturbance area, whereas uric acid increased in individuals from the disturbed area, indicating a poorer body condition of penguins under anthropogenic pressure. Immune responses were elevated in penguins from the disturbed area (IgY, γ-globulins and hemagglutinating activity). Finally, individuals breeding under anthropogenic pressure overexpressed proteins with immune, antioxidant, and metabolic functions. The poor nutritional status of penguins under disturbance may be the consequence of the reallocation of resources to the immune system. Altogether, this would constitute a potential strategy to preserve an adequate immune phenotype under stressed environments.