Early development conditions and the oxidative cost of social context in adulthood: an experimental study in birds

Abstract

Environmental conditions during early life may shape phenotype in adulthood. Early adverse conditions may increase the oxidative stress in adults, which could affect their reproductive output and survival. It has also been hypothesized that the larger the reproductive investment, the higher the oxidative stress. We tested this and the potential influence of early oxidative stress on how individuals respond to a reproductive stimulation. The synthesis of the antioxidant glutathione was inhibited in captive zebra finches (Taeniopygia guttata) during growth. In adulthood, the expression of a carotenoid-based sexual signal, bill redness, increased in both sexes, with females also being heavier than controls. The social context of control and glutathione-inhibited males was then manipulated to stimulate precopulatory reproductive investments. Males were individually caged in front of a female or another male. We predicted that males enduring lower early antioxidant levels and placed close to a female should pay the highest cost of a hypothetical increase in bill redness in terms of oxidative damage. However, early conditions only influenced the male's phenotype via their partners. Males caged with females showed increases in circulating pigment (carotenoid) levels, but only when females endured early low antioxidant values. This was probably related to the higher attractiveness of these females. Nevertheless, the bill redness of males did not differ during the social manipulation. Moreover, males facing females from any early condition group showed lower oxidative damage levels in plasma lipids. This result agrees with some findings in rodents, also in captivity. However, the effect may be due to increased triglyceride levels and body mass in males not facing females, as variation in these traits explained oxidative damage variability. The importance of considering housing conditions and life history when interpreting oxidative stress-related trade-offs is highlighted.

The oxidative cost of reproduction depends on early development oxidative stress and sex in a bird species

“…The statistical models reported here did not correspond to any test published from the same zebra finch population in previous studies (i.e. [25,26]). A subsample of those birds is used and a new life period studied.…”

“…100 days old approximately) to perform a fourweek long experiment where males were housed in front of males or females in order to test the influence of adult social conditions on sexual signalling and physiology (i.e. [26]). Both males and females in this study were involved in that experiment.…”

“…Half of the birds underwent a transient artificial reduction in their capacity to synthesize the most important intracellular antioxidant (i.e. glutathione) during growth [25,26]. In adulthood, the birds were allowed to mate and breed freely in an outdoor aviary.…”

Specific carotenoid pigments in the diet and a bit of oxidative stress in the recipe for producing red carotenoid-based signals

“…In all the mixed models testing the diquat effect, plasma vitamin levels in the last sampling event, as well as vitamin levels in every internal tissue and ornaments, were also added. In models testing plasma MDA values, plasma triglyceride levels were added to control for potential influences of lipid variability in the blood ( Romero-Haro & Alonso-Alvarez, 2014 ; Romero-Haro, Canelo & Alonso-Alvarez, 2015 ). In models testing PLAOX, uric acid, and albumin values were simultaneously tested to control for influences of recent food intake ( Cohen, Klasing & Ricklefs, 2007 ).…”

Dietary canthaxanthin reduces xanthophyll uptake and red coloration in adult red-legged partridges

“…Note that contrary to the diet data shown in Table 1, canthaxanthin-treated animals showed lower lutein and zeaxanthin levels in blood or liver compared with controls. In models testing plasma MDA levels, plasma triglyceride levels were added to control for potential influences of lipid variability in the blood (Romero-Haro and Alonso-Alvarez, 2014; Romero-Haro et al, 2015;Pérez-Rodríguez et al, 2015). In models testing PLAOX, uric acid and albumin levels were simultaneously tested to control for the influence of recent food intake (Cohen et al, 2007).…”