Self-supplementation and effects of dietary antioxidants during acute thermal stress

Beaulieu, Michaël; Haas, Anabel; Schaefer, H. Martin

doi:10.1242/jeb.092825

Cited by 19 publications

(12 citation statements)

References 50 publications

(73 reference statements)

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“…Recent research suggests birds self-medicate with antioxidants (62) . Birds challenged by an increased production of reactive oxygen species after long flights (9) or under thermal stress (63) preferentially select foods high in flavonoids : parasitised animals (data taken from Villalba et al (32) ). : naive control animals; : parasitised animals (data taken from Juhnke et al (33) ).…”

Section: Proceedings Of the Nutrition Societymentioning

confidence: 99%

Phytochemicals in animal health: diet selection and trade-offs between costs and benefits

2016

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Many plant tissues contain plant secondary compounds (PSC), which have long been recognised as defensive chemicals that deter herbivory via their toxic effects. However, herbivores may also benefit from including PSC into their diets. Plant-derived phenolics, terpenes and alkaloids have antiparasitic properties and sesquiterpene lactones have antibacterial, antifungal and antiparasitic properties. These actions are in part a consequence of the negative actions that PSC exert across several trophic levels, including the bacteria, parasites and fungi that inhabit herbivores' bodies. Given the dual action, toxin and medicine, it is possible to hypothesise that self-selection of PSC by herbivores should occur when the benefits outweigh the costs of PSC ingestion. Recent research suggests that sheep and goats self-medicate against parasitic infections. They increase preference for condensed tannin-containing foods when experiencing a parasitic burden. This behaviour improves health; it is triggered by parasitism and weakens when parasitism subsides. However, the causes underlying these responses are not straightforward when viewed under a unidimensional cost-benefit analysis. This is because the intensity of antinutritional/toxic and medicinal effects of PSC is not static or just dependent upon the isolated post-ingestive effects of single PSC. Nutrient-PSC and PSC-PSC interactions, social models, as well as feeding patterns, all influence the perceived net benefit of incorporating medicines into a diet. A better understanding of the net benefit of self-medication in complex feeding environments will allow for the development of innovative managing strategies aimed at providing the food alternatives and conditions for improving the nutrition, health and welfare of grazing animals.

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Section: Proceedings Of the Nutrition Societymentioning

confidence: 99%

Phytochemicals in animal health: diet selection and trade-offs between costs and benefits

2016

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“…Although some of the factors (e.g., diet quality) may be controlled to some extent in captivity experiments, other important issues may arise. For example, granivorous songbird individuals may select seeds richer in antioxidants when facing challenging conditions (Beaulieu et al, 2014). Moreover, it is often forgotten that preventing individuals from reproducing is not a natural condition nor is it a free choice of the individual.…”

Section: A Commentary Onmentioning

confidence: 99%

Commentary: Oxidative stress as a cost of reproduction: beyond the simplistic trade-off model

Costantini

2016

Front. Ecol. Evol.

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A commentary onOxidative stress as a cost of reproduction: beyond the simplistic trade-off model by Speakman, J. R., and Garratt, M. (2014). Bioessays 36, 93-106. doi: 10.1002/bies.201300108 Current theory proposes that life history traits cannot be simultaneously maximized because there are costs paid in the currency of fitness when a change in one trait, for example increased reproduction, results in a detrimental change in another, for example decreased survival. The underlying reasoning is that resources (e.g., nutrients, energy, time) are finite and this gives rise to trade-offs in their allocation among traits, activities, or processes that compete for the same resource. Therefore, allocation of a resource to one trait means that less can be invested to other traits. This simple concept, referred to as a trade-off, has had a prominent role in our understanding of how life history variation arises.We currently know very little about how these costs of reproduction are actually incurred, since the majority of studies have focussed on the outcomes rather than the mechanisms. In the last decade, there has been substantial interest in the role of oxidative stress as a mechanism underlying the cost of reproduction and other life-history trade-offs. Oxidative stress is a complex multifaceted biochemical condition of the organism that occurs when generation of oxidative molecular damage increases (Costantini, 2008(Costantini, , 2014Metcalfe and Alonso-Alvarez, 2010;Isaksson et al., 2011). Several recent studies have, however, found weak or no support that reproductive effort increases oxidative damage (Costantini, 2014). In a recent article, Metcalfe and Monaghan (2013) have pointed out that several of these studies testing the role of oxidative stress as a cost of reproduction did not include data on non-breeding controls, making it hard to exclude seasonal or ontogenetic causes of changes in oxidative stress. They also highlighted, however, that females may tailor their own level of reproduction to avoid oxidative damage, hence it would be also important to manipulate the reproductive effort. In another article, Speakman and Garratt (2014) reinforced the idea of testing the oxidative cost of reproduction by randomly assigning animals to two groups, one of which is forced to reproduce and another one that is prevented from doing so. This is because even if individuals can choose their level of reproduction, what they cannot avoid, is an increase in metabolic rate, relative to a non-reproductive control animal. Recent experimental meta-analytic (Blount et al., 2015) work has, however, found that oxidative damage is lower in reproducing than in non-reproducing individuals, providing again little support for the oxidative cost of reproduction hypothesis.An important question then is whether non-reproducing individuals are truly appropriate controls. The answer does not seem to be so straightforward. Non-reproducing individuals may differ from reproducing individuals in several characteristics, which might make ...

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“…All the breeding and non-breeding birds were maintained in a same room on a 14 h:10 h light:dark photoperiod and room temperature of 19-23°C. The room temperature was within the thermoneutral zone of canaries (Weathers, 1985); note that at ambient temperatures outside this zone both metabolic and oxidative costs increase (Weathers, 1985;Beaulieu et al, 2014). We initially had 46 pairs allocated to the breeding group and 23 pairs allocated to the non-breeding group.…”

Section: Housing Conditions and Experimental Setupmentioning

confidence: 99%

Does reproduction protect against oxidative stress?

Casasole

Eens

2014

Journal of Experimental Biology

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A central principle of life-history theory is that parents trade investment in reproduction against that in body maintenance. One physiological cost thought to be important as a modulator of such trade-off is oxidative stress. Experimental support for this hypothesis has, however, proved to be contradictory. In this study, we manipulated the nestling rearing effort of captive canaries (Serinus canaria) soon after the hatching of their nestlings using a brood-size manipulation to test whether an increase in nestling rearing effort translates into an increase in oxidative damage, an increase in ceruloplasmin (which is upregulated in response to oxidative damage) and a decrease in thiol antioxidants. We also compared the blood oxidative stress level of reproducing birds with that of nonreproducing birds, a crucial aspect that most studies have invariably failed to include in tests of the oxidative cost of reproduction. Compared with non-breeding canaries and pre-manipulation values, plasma oxidative damage (reactive oxygen metabolites and protein carbonyls) decreased in breeding canaries irrespective of sex and brood size. In contrast, oxidative damage did not change in nonbreeding birds over the experiment. Ceruloplasmin activity in plasma and both non-protein and protein thiols in red blood cells did not change throughout the experiment in both treatment groups. Our results suggest that reproduction may result in decreased rather than increased blood oxidative stress. Our results may explain some of the inconsistencies that have so far been reported in experimental tests of the oxidative cost of reproduction hypothesis.

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Self-supplementation and effects of dietary antioxidants during acute thermal stress

Cited by 19 publications

References 50 publications

Phytochemicals in animal health: diet selection and trade-offs between costs and benefits

Phytochemicals in animal health: diet selection and trade-offs between costs and benefits

Commentary: Oxidative stress as a cost of reproduction: beyond the simplistic trade-off model

Does reproduction protect against oxidative stress?

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