Effects of Sibling Competition on Growth, Oxidative Stress, and Humoral Immunity: A Two-Year Brood-Size Manipulation

Abstract

We investigated the effects of ecological context (by comparing data from two consecutive years) and experimentally manipulated nestling developmental conditions (large vs. small brood size) on immune function (immunoglobulin Y [IgY]) and oxidative stress in nestling European starlings Sturnus vulgaris. On the basis of annual differences in chicks' morphological traits and body masses close to fledging, we established that 2007 was a relative low-quality year and 2008 was a relatively high-quality year. Total antioxidant capacity (TAC) was significantly lower in experimentally enlarged broods, but only in the low-quality year (2007). Total oxidant status (TOS) was independent of brood size in both years but was 45% higher in the low-quality year. Consequently, plasma oxidative status (the ratio between TOS and TAC) was higher in 2007. In contrast, plasma IgY levels were higher in the experimentally enlarged broods and in the high-quality year (2008). Thus, immune function and oxidative stress showed inverse relationships with developmental conditions and annual variation in year quality. Finally, TOS and TAC were positively correlated, but only in the low-quality year (2007), and there was no relationship observed between IgY and markers of oxidative stress. Our results demonstrate the importance of taking into account year effects or ecological context when assessing environmental effects on physiological mechanisms underlying the life-history traits of chicks, such as oxidative stress.

Bill size correlates with telomere length in male American Redstarts

“…Indeed, bill size may mainly depend on developmental conditions whereas tarsus size may be mainly determined by a genetic component in Redstarts, as previously found in another passerine species (Keller et al 2001). Supporting the idea that tarsus length may not be primarily determined by developmental conditions, Bourgeon et al (2011) found that wing length, but not tarsus length, reach smaller size when European Starling (Sturnus vulgaris) chicks are bred under poor J Ornithol (2015) 156:525-531 529 developmental conditions (enlarged brood and strong sibling competition). Interestingly, we found that AHY birds had larger tarsus, but not bill, than HY birds.…”

“…During the development, environmental constraints are known to, respectively, increase oxidative stress and reduce growth (Alonso-Alvarez et al 2007;Costantini 2010;Kim et al 2011;Bourgeon et al 2011), suggesting that the specific conditions of this developmental phase may be responsible for a potential relationship between adult body size and telomere length (Geiger et al 2012). Indeed, growth is slowed down and individuals usually reach small adult size when reared under poor conditions.…”

Antioxidant defense system and family environment in adolescents with family history of psychosis

“…Results from animal models have shown that poorer environmental conditions are associated with more oxidative stress [13], and this is probably due to the need to transfer energy towards processes with a high energy cost, such as immune function, antioxidant defence and DNA repair processes [14]. The relationship between environmental conditions and oxidative stress has not been examined in healthy humans.…”

On the methodological limitations of detecting oxidative stress: effects of paraquat on measures of oxidative status in greenfinches

“…Arnold et al, 2010;Costantini, 2010;Bourgeon et al, 2011), strenuous exercise (e.g. Neubauer et al, 2010;Beaulieu et al, 2011), administration of testosterone Tobler and Sandell, 2009) or glucocorticoid hormones (reviewed by Costantini et al, 2011).…”