Is oxidative status influenced by dietary carotenoid and physical activity after moult in the great tit (Parus major)?

Abstract

In the context of sexual and natural selection, an allocation trade-off for carotenoid pigments may exist because of their obligate dietary origin and their role both in the antioxidant and immune systems and in the production of coloured signals in various taxa, particularly birds. When birds have expended large amounts of carotenoids to feather growth such as after autumn moult, bird health and oxidative status might be more constrained. We tested this hypothesis in a bird species with carotenoid-based plumage colour, by manipulating dietary carotenoids and physical activity, which can decrease antioxidant capacity and increase reactive oxygen metabolite (ROM) concentration. Great tits were captured after moult and kept in aviaries, under three treatments: physical handicap and dietary supplementation with carotenoids, physical handicap and control diet, and no handicap and control diet. We measured plasma composition (antioxidant capacity, ROM concentration, and vitamin A, vitamin E and total carotenoid concentrations), immune system activation (blood sedimentation) and stress response (heterophil/ lymphocyte ratio) and predicted that handicap treatment should influence these negatively and carotenoid supplementation positively. Coloration of yellow feathers was also measured. Carotenoid supplementation increased total plasma carotenoid concentration, decreased feather carotenoid chroma and marginally increased ROM concentration. Handicap increased blood sedimentation only in males but had no clear influence on oxidative stress, which contradicted previous studies. Further studies are needed to investigate how physical activity and carotenoid availability might interact and influence oxidative stress outside the moult period, and their combined potential influence on attractiveness and reproductive investment later during the breeding season.

The role of the antioxidant system during intense endurance exercise: lessons from migrating birds

“…This suggests that GPx was upregulated in response to RS-mediated damage during flight, although not to the extent that damage was entirely avoided. Accordingly, plasma non-enzymatic antioxidants were higher in great tits (Parus major) with clipped feathers (which increases flight effort) than in individuals with unclipped feathers (Vaugoyeau et al, 2015). Interestingly, zebra finches (Taeniopygia guttata) flown at rapid speeds had increased levels of plasma uric acid but not antioxidant enzymes compared with those of control birds (Costantini et al, 2013).…”

“…For example, carotenoids seem to inhibit lipid peroxidation at low oxygen concentrations, but not at high oxygen concentrations (Hatta and Frei, 1995); although carotenoids are able to neutralize RS, the contribution of carotenoids to plasma antioxidant capacity is small (Costantini and Møller, 2008). Great tits supplemented with carotenoids and experimentally manipulated to increase physical activity showed increased circulating carotenoid concentrations, but also displayed increased oxidative damage and reduced antioxidant capacity (Vaugoyeau et al, 2015). Therefore, the role of carotenoids as potent antioxidants is debated (Costantini and Møller, 2008;Halliwell and Gutteridge, 2007;Hill and Johnson, 2012;Marri and Richner, 2014;Pamplona and Costantini, 2011), and recent research has emphasized that carotenoids may act as a signal for oxidative health rather than as antioxidants themselves (Costantini and Møller, 2008;Hill and Johnson, 2012;Johnson and Hill, 2013).…”

How does an increase in minimum daily temperatures during incubation influence reproduction in the great tit Parus major?

“…Smears were examined under oil immersion at 1000  magnification and the different types of leucocytes in a total of 50 leucocytes per smear were counted in random order by the same person (MV). Only a maximum of 50 leucocytes could be found (as in Vaugoyeau et al 2015 and not 100 as in other studies (Hõrak et al 1998, Cirule et al 2012, Banbura et al 2013) due to a lack of leucocytes (mean  SE leucocytes per examination of 10 000 erythrocytes  26  17 as compared to other studies in great tits: 90  30 (Cirule et al 2012) and 50  23 ). Repeatability scores of our counts were highly significant (H/Ly: F 53,54  63.93, p  0.01, intraclass correlation coefficient  0.97 (Lessells and Boag 1987)).…”

“…Blood smears were air‐dried, fixed in absolute methanol and stained with Giemsa (Sigma Giemsa modified 0.4% p/v) (Vaugoyeau et al ). Smears were examined under oil immersion at 1000 × magnification and the different types of leucocytes in a total of 50 leucocytes per smear were counted in random order by the same person (MV).…”

Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

“…Both the intensity and the proportion of red-yellow-orange birds differ geographically (e.g., Massa 1987) but also seasonally within areas (Alonso and Arizaga 2013). In general, it is stated that red is the most 'expensive' colour that a Crossbill is able to produce because the red coloration arises from yellow carotenoids already present in the diet but only if conditions linked to oxidative processes happen (Stradi 1998;Inouye 1999;García de Blas et al 2016;Vaugoyeau et al 2015). This oxidation occurs only in some individuals (e.g., Vaugoyeau et al 2015).…”