No Effect of Carotenoid Supplementation on Phytohemagglutinin Response or Body Condition of Nestling House Wrens

Abstract

Carotenoids are an essential and often limiting resource in animals and play important roles in immune system function. In birds, the period shortly after hatching is an energetically demanding stage characterized by rapid growth in body size and organ systems, including the immune system. Availability of carotenoids for the growing nestlings may be of particular importance and potentially limiting at this stage of development. We tested the hypothesis that the availability of carotenoids for the embryo in the egg and in the diet of nestlings limits the condition and immune responses of nestling house wrens (Troglodytes aedon Vieillot 1809), a species with melanin-based plumage pigments. In one experiment, nestlings within females' second broods were randomly assigned to receive either a control or a lutein supplement (2008); in a second experiment, females, before their first broods, were either induced to lay additional eggs or not induced, and nestlings within both kinds of broods were supplemented as in the first experiment (2009). There were no significant effects of lutein supplementation on nestling condition or phytohemagglutinin response. There was a significant effect of lutein supplementation on nestling mass in 2008, but the difference was opposite to that predicted. Moreover, even when breeding females were stressed by inducing them to lay supernumerary eggs, lutein supplementation of nestlings had no effect on the size or condition of nestlings hatching from these eggs. These results suggest that maternally derived lutein in the egg and that provided in the diet of nestlings are not limiting to normal development and to the components of the immune system involved in the phytohemagglutinin response of nestling house wrens.

Genetic and environmental variation in condition, cutaneous immunity, and haematocrit in house wrens

“…Nest effects accounted for over half the phenotypic variation in nestling PHA response, a result consistent with previous studies in this population showing that hatching date and time of injection can influence PHA response of nestling house wrens [ 24 , 25 , 41 , 66 ]. Additional environmental factors might also include food availability, temperature, and parasite load [ 12 ], and we also cannot rule out the possibility of parental effects arising from differential provisioning of broods [ 39 , 55 ] or transgenerational priming of immunity arising from the transfer of maternal antibodies in eggs [ 67 ].…”

What are carotenoids signaling? Immunostimulatory effects of dietary vitamin E, but not of carotenoids, in Iberian green lizards

“…Contrary to our results, several studies in birds and fish have found a positive effect of dietary carotenoids on the PHA skin swelling immune response (Blount et al 2003;McGraw and Ardia 2003;Aguilera and Amat 2007;Clotfeltera et al 2007;Stirnemann et al 2010), or found that the immune response depletes available carotenoids (McGraw and Ardia 2003;Alonso-Álvarez et al 2004;Aguilera and Amat 2007;Pérez-Rodríguez et al 2008) or found a positive relationship between circulating carotenoid levels and the magnitude of the immune response (McGraw and Ardia 2003;Pérez-Rodríguez et al 2008). However, many other studies of birds and fish show a lack of effects of carotenoid supplementation on the immune response (Navara and Hill 2003;McGraw and Ardia 2005;Biard et al 2006;Hõrak et al 2006Hõrak et al , 2007McGraw and Klasing 2006;Lin et al 2010;Sutherland et al 2012).…”

“…In some growing nestlings bird species, carotenoid supplementation may also increase body condition by regulating oxidative stress resulting from rapid growth (Biard et al 2006), although in other fish and bird species there are no effects (e.g. Pike et al 2010;Sutherland et al 2012), probably because natural food might contain sufficient carotenoids to obscure any benefit of carotenoid supplementation. A similar positive effect of carotenoids on body condition might occur in lizards which have continuous growth and, in our captivity experiment, only have access to some prey types that might not contain enough natural carotenoids.…”

“…There are controversial results on the immunostimulatory effect of carotenoids; several studies have found a positive relationship between carotenoids and some aspects of the immune response in birds (Blount et al 2003;McGraw and Ardia 2003;Aguilera and Amat 2007;Stirnemann et al 2010) and fish (Amar et al 2000(Amar et al , 2001(Amar et al , 2004Clotfelter et al 2007), but there are also many examples demonstrating a lack of association both in birds (Navara and Hill 2003;McGraw and Ardia 2005;Biard et al 2006;Hõrak et al 2006;McGraw and Klasing 2006;Sutherland et al 2012) and fish (Lin et al 2010). A meta-analysis shows a low effect size for the relationships of circulating carotenoid level with immunocompetence and oxidative stress in birds, suggesting that these relationships might not be causal and that complementary mechanisms maintaining honesty might be involved (Simons et al 2012).…”

Age‐related prenatal maternal effects and postnatal breeding experience have different influences on nestling development in an altricial passerine

“…This is in contrast to findings from similar studies where heritable and/or early maternal effects explained part of the variance in the strength of nestling immune responses to external pathogens (full cross-fostering: Morrison et al 2009; partial cross-fostering: Drobniak et al 2015; but see Saino et al 2008, Rutkowska et al 2012). Investment of anti-oxidants into eggs, such as carotenoids (Berthouly et al 2008, De Neve et al 2008; but see Sutherland et al 2012) and immune factors (Pihlaja et al 2006), have been experimentally demonstrated to influence nestling immunocompetence, we expected a maternal age effect on this trait. Similarly, since nest microclimate and daytime temperature during the brood-rearing period correlate with survival in many species (Monrós et al 2002).…”