Birds receiving extra carotenoids keep singing during the sickness phase induced by inflammation

Abstract

Life history theory predicts that individuals have to trade-off resources between diverse energy-demanding activ- ities, such as mounting an immune response and performing advertisement behaviour. The availability of immunomodula- tory micronutrients can affect this trade-off. Carotenoids can upregulate both the humoral and cell-mediated immune re- sponse, but little is known about their effect on behavioural traits during the sickness phase induced by a common inflam- mation. To investigate whether dietary carotenoids can miti- gate the severity of the sickness syndrome and promote fitness-related traits, we studied how the song rate of captive male European starlings (Sturnus vulgaris, Linnaeus 1758) receiving dietary carotenoids and coping with a challenge (li- popolysaccharide, LPS) mimicking a bacterial infection var- ied during the sickness phase and the subsequent recovery phase. We found that birds not provisioned with carotenoids and injected with LPS sang less than control birds during the sickness phase, but not during the recovery phase.Conversely, birds provided access to a carotenoid-enriched diet never de- creased their song rate. Our results show that immune- challenged birds have to trade-off between mounting an im- mune response and advertising only when their access to die- tary carotenoids is limited. No differences in song rate were observed between treatments during the recovery phase. Our study is the first to investigate the role of dietary carotenoids Communicated by K.McGraw * Stefania Casagrande scasagrande@orn.mpg.de 1 Department of Biology, Ethology Group, University of Antwerp, Antwerp, Belgium 2 Institute for Education and Information Sciences, Research Unit Didactica, University of Antwerp, Antwerp, Belgium on a behavioural syndrome-like sickness and to show that providing a carotenoid-rich diet can alleviate the social costs associate

Honest Signaling and Oxidative Stress: The Special Case of Avian Acoustic Communication

“…In the last decades several studies have investigated the role of the redox state in mediating the expression of visual secondary sexual traits (Alonso-Alvarez et al, 2007;McGraw, 2008;Svensson and Wong, 2011;Garratt and Brooks, 2012;Hill and Johnson, 2012;Simons et al, 2012), but until now only few of them focused on birdsong (Van Hout et al, 2011;Casagrande et al, 2014Casagrande et al, , 2015Baldo et al, 2015;Costantini et al, 2015; Table 1). Studies carried out in captive male European starlings (Sturnus vulgaris) to investigate whether song activity can honestly convey information about the redox state, reported that the administration of dietary lutein through the diet was associated with an increase in song rate (Van Hout et al, 2011;Casagrande et al, 2014Casagrande et al, , 2015.…”

“…Studies carried out in captive male European starlings (Sturnus vulgaris) to investigate whether song activity can honestly convey information about the redox state, reported that the administration of dietary lutein through the diet was associated with an increase in song rate (Van Hout et al, 2011;Casagrande et al, 2014Casagrande et al, , 2015. Lutein is a hydroxycarotenoid synthetized by autotrophic organisms as an essential photosynthetic pigment.…”

Experimental inhibition of a key cellular antioxidant affects vocal communication

“…Recent studies in male European starlings found that inflammatory processes significantly decreased song rate (Casagrande et al . ) and that the antibody production caused a moderate reduction of one particular mode of singing (undirected song rate, i.e. song produced away from the nest‐box; Costantini et al .…”

Early exposure to a bacterial endotoxin advances the onset of moult in the European starling

“…Various studies show that birds undergo several hormonal and behavioural alterations when exposed to lypopolysaccharide (LPS), an endotoxin extracted from the outer membrane of Gram‐negative bacteria that elicits an immune response in the absence of a living pathogen (Bonneaud et al , Munoz et al , Casagrande et al ). In the barn swallow, for example, nestlings injected with LPS showed a reduced growth rate, an increased occurrence of fault bars in growing feathers (Romano et al ), and a lower breeding success (expressed as the ratio between paired and recruited males) in the following breeding season (Romano et al ).…”

“…In two studies on adult pied flycatchers Ficedula hypoleuca , LPS‐injected males (Sanz et al ) and females (Ilmonen et al ) showed delayed moult onset and inhibited tail feather regrowth, respectively. Adult starlings injected with LPS reduced their song rate when exposed to a standard diet, but not when supplemented with carotenoids (Casagrande et al ).…”