Non‐specific Antimicrobial Defences of the Avian Egg, Embryo and Neonate

Board, R. G.; Fuller, R.

doi:10.1111/j.1469-185x.1974.tb01297.x

Cited by 121 publications

(73 citation statements)

References 131 publications

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“…Indeed, the high rate of extra-pair mating in tree swallows (Whittingham and Dunn, 2001) makes it unlikely that the relationship between male coloration and offspring immunity is attributable to genetic inheritance alone. This relationship could also be the result of a maternal effect if brighter white females deposit more carotenoids (Saino et al, 2003;Biard et al, 2007), antibodies (Hasselquist and Nilsson, 2009), lysozyme (Board and Fuller, 1974) or testosterone (Clairardin et al, 2011) in eggs, which can all influence the immunocompetence of their offspring. While beyond the scope of the current study, future work should assign parentage to offspring and employ a cross-fostering design to better disentangle the contributions of genetics, micronutrient availability and other parental effects on offspring immunity.…”

Section: Discussionmentioning

confidence: 99%

Relationships among plumage coloration, blood selenium concentrations, and immune responses of adult and nestling tree swallows

Beck

Hawley

2015

Journal of Experimental Biology

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In a number of taxa, males and females both display ornaments that may be associated with individual quality and could be reliable signals to potential mates or rivals. We examined the iridescent blue/green back and white breast of adult tree swallows (Tachycineta bicolor) to determine whether plumage reflectance is related to adult or offspring immune responses. We simultaneously addressed the influence of blood selenium levels and the interaction between blood selenium and plumage coloration on adult and nestling immunity. Selenium is a wellknown antioxidant necessary for mounting a robust immune response but its importance in wild birds remains poorly understood. In females, the brightness of white breast coloration was positively associated with bactericidal capacity, but there was no association with blood selenium. In contrast, male bactericidal capacity was associated with an interactive effect between dorsal plumage coloration and blood selenium concentration. Males with bluer hues and greater blue chroma showed increased bactericidal capacity as blood selenium concentrations increased, while bactericidal capacity declined in greener males at higher blood selenium concentrations. In nestlings, bactericidal capacity was positively associated with nestling blood selenium concentrations and white brightness of both social parents. These results suggest that white plumage reflectance is indicative of quality in tree swallows and that greater attention should be paid to the reflectance of large white plumage patches. Additionally, the role of micronutrients, such as selenium, in mediating relationships between physiology and signals of quality, should be explored further.

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Section: Discussionmentioning

confidence: 99%

Relationships among plumage coloration, blood selenium concentrations, and immune responses of adult and nestling tree swallows

Beck

Hawley

2015

Journal of Experimental Biology

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“…the presence of more potent antimicrobial proteins in the eggshells of cavity-nesting versus open cup-nesting Anseriform species . Deposition of antimicrobial proteins in eggs is not a costly investment for mothers (Shawkey et al, 2008); however, it is possible that an increase in their content conflicts with the existence of different developmental demands of the embryos, including optimal water uptake, gas exchange, mobilization of nutrients within the egg and structural support to growing embryos (Board and Fuller, 1974). Inhibiting growth of pathogenic bacteria on the outer surface of the egg might be a more efficient way to prevent infection without compromising the properties of albumen.…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial properties of a nanostructured eggshell from a compost-nesting bird

D’Alba

Jones

Badawy

et al. 2013

Journal of Experimental Biology

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Infection is an important source of mortality for avian embryos but parental behaviors and eggs themselves can provide a network of antimicrobial defenses. Mound builders (Aves: Megapodiidae) are unique among birds in that they produce heat for developing embryos not by sitting on eggs but by burying them in carefully tended mounds of soil and microbially decomposing vegetation. The low infection rate of eggs of one species in particular, the Australian brush-turkey (Alectura lathami), suggests that they possess strong defensive mechanisms. To identify some of these mechanisms, we first quantified antimicrobial albumen proteins and characterized eggshell structure, finding that albumen was not unusually antimicrobial, but that eggshell cuticle was composed of nanometer-sized calcite spheres. Experimental tests revealed that these modified eggshells were significantly more hydrophobic and better at preventing bacterial attachment and penetration into the egg contents than chicken eggs. Our results suggest that these mechanisms may contribute to the antimicrobial defense system of these eggs, and may provide inspiration for new biomimetic anti-fouling surfaces.

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“…Eggs possess physical and chemical mechanisms to protect against microbial invasion (Board 1966;Board & Fuller 1974) and the effectiveness of defence depends on the environmental conditions and the attributes of invading organisms (Board & Tranter 1986). Micro-organisms enter the egg through the small proportion of eggshell pores that are not covered by the shell cuticle (Board & Board 1967).…”

Section: Introductionmentioning

confidence: 99%

Trans–shell infection by pathogenic micro–organisms reduces the shelf life of non–incubated bird's eggs: a constraint on the onset of incubation?

Cook

Beissinger

Toranzos

et al. 2003

Proc. R. Soc. Lond. B

162

230

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Many birds initiate incubation before clutch completion, which results in asynchronous hatching. The ensuing within-brood size disparity often places later-hatched nestlings at a developmental disadvantage, but the functional significance of the timing of the onset of incubation is poorly understood. Early incubation may serve to maintain the viability of early-laid eggs, which declines over time owing to the putative effects of ambient temperature. An unexplored risk to egg viability is trans-shell infection by micro-organisms. We experimentally investigated the rate and magnitude of microbial trans-shell infection of the egg, and the relative effects of ambient temperature and micro-organisms on hatching success. We show that infection of egg contents is prevalent and occurs within the time required to lay a clutch. The probability of infection depends on the climatic conditions, the exposure period and the phylogenetic composition of the eggshell microbiota. We also demonstrate that microbial infection and ambient temperature act independently to reduce egg viability considerably. Our results suggest that these two factors could affect the onset of avian incubation in a wide range of environments.

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Non‐specific Antimicrobial Defences of the Avian Egg, Embryo and Neonate

Cited by 121 publications

References 131 publications

Relationships among plumage coloration, blood selenium concentrations, and immune responses of adult and nestling tree swallows

Relationships among plumage coloration, blood selenium concentrations, and immune responses of adult and nestling tree swallows

Antimicrobial properties of a nanostructured eggshell from a compost-nesting bird

Trans–shell infection by pathogenic micro–organisms reduces the shelf life of non–incubated bird's eggs: a constraint on the onset of incubation?

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