Impacts of dietary antioxidants and flight training on post-exercise oxidative damage in adult parrots

SUMMARYOne cellular mechanism thought to be particularly important as a constraint on lifespan and life-history strategies is oxidative stress. Susceptibility to oxidative stress is influenced by a number of antioxidant defences, whose effectiveness depends on the synergistic and competitive interactions among them (biochemical integration). It is generally assumed that exposure to oxidative stress is detrimental, but it is also possible that low level oxidative stress has a positive effect on integration, and therefore carries some benefits. Using three experimental groups of zebra finches (control, mild and high flight activity), we tested whether exercise-induced oxidative stress altered the integration of the pro-oxidant/antioxidant system by manipulating levels of flight activity, known to generate oxidative stress in birds. We show for the first time that a short-term high level of physical activity leads to a reduction in integration among components of the blood antioxidant defences, associated with a reduced resistance to oxidative stress. We found no evidence of improved integration in the antioxidant defences at low levels of oxidative stress exposure, suggesting that improved integration is not the route whereby any benefits of low level stress exposure occur. These findings point to a reduction in biochemical integration as a potential mechanism explaining a reduced resistance to oxidative stress induced by short-term stressors. Supplementary material available online at

Section: Discussionmentioning

confidence: 99%

Loss of integration is associated with reduced resistance to oxidative stress

Costantini

Monaghan

Metcalfe

2013

“…Moreover, food was given ad libitum and might be more caloric and/or richer in antioxidants, than that found in natural conditions at that time of year (Sanz et al, 2000;Patterson et al, 2011), which could have buffered the expected effect of plucking some wing feathers on ROM concentration. Birds may not have been significantly constrained with regard to the availability of energy or antioxidants that are needed to activate repair pathways (Finkel and Holbrook, 2000;Larcombe et al, 2008Larcombe et al, , 2010 and may have thus overcome the physical handicap without increasing ROM concentration. However, the effects of physical activity on ROM concentration may also depend on other factors such as age (Finkel and Holbrook, 2000;Costantini et al, 2008), or pollutants (Koivula and Eeva, 2010).…”

Section: Discussionmentioning

confidence: 99%

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

Vaugoyeau

Decencière

Perret

et al. 2015

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.

“…Wild (active) birds may also differ in their efficiency at meeting such demands. For example, previously 'unfit' captive budgerigars (Melopsittacus undulatus) showed reduced MDA following weeks of regular flight training (Larcombe et al, 2010a). The lack of direct correlation between OXY, ROMs and MDA may similarly be explained by undemanding living conditions: in humans, lipid peroxidation and plasma antioxidant levels are often uncorrelated in healthy subjects, but correlated in subjects under heightened physiological demands; for example, negatively in individuals with pathological diseases but increasingly positively in subjects in exercise studies (for a review, see Dotan et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…Costantini et al, 2007;Costantini and Bonadonna, 2010;Larcombe et al, 2008). Across individuals (regardless of personality), body mass may also affect pro-oxidant production, as very high and very low mass are both associated with increased oxidative stress (Costantini et al, 2007;Larcombe et al, 2010a;Wiersma et al, 2004). Therefore, we also investigated the effects of body mass on oxidative profile.…”

Section: Introductionmentioning

confidence: 99%

Oxidative profile varies with personality in European greenfinches

Herborn

Coffey²,

Larcombe³

et al. 2011

SUMMARYWhere behavioural responses differ consistently between individuals, this is termed 'personality'. There is the suggestion, but with little supporting data, that personality traits reflect underlying variation in physiology. Here, we tested whether greenfinches Carduelis chloris differing in personality traits differed in various plasma indices of oxidative profile: antioxidant capacity (OXY), pro-oxidant status (reactive oxygen metabolites, ROMs), oxidative stress (OS) and an end-product of oxidative damage: malondialdehyde (MDA). We measured two personality traits: neophobia (latency to approach food near novel objects) and object exploration (latency to approach novel objects). These traits were uncorrelated. ROMs, OXY, OS and MDA were also uncorrelated with each other. Highly neophobic birds had lower OXY, higher ROMs and higher OS than less neophobic birds. Fast exploring birds had higher OXY than slow explorers, but did not differ in ROMs or OS. Variation in MDA was described by a quadratic relationship with neophobia: birds with extremely high or low neophobia had lower MDA than birds with intermediate neophobia, despite highly neophobic birds exhibiting lower OS than intermediately neophobic birds. Additively in that model, fast explorers had lower MDA than slower explorers. To conclude: first, personality types can differ in oxidative profile. Second, although physiological differences (e.g. hormonal stress responsiveness) between personality types generally range along a linear continuum, physiological costs may not. Finally, relationships with oxidative profile differed between neophobia and object exploration. Understanding how oxidative profile and thus physiological costs vary within and between personality traits may explain how differences in personality traits can predict fitness.