Eggshell strength: A relationship between the mechanism of failure and the ultrastructural organisation of the mammillary layer

Bain, M.

doi:10.1080/00071669208417469

Cited by 74 publications

(56 citation statements)

References 17 publications

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“…The highest mean values of these indicators were found in the enriched cages. Bain (1992) in accordance with results of this study reported a thinning of the eggshell with an increasing number of laying hens per area unit. Leyendecker et al (2002) and Pistekova et al (2006), unlike other researchers, found no significant differences in eggshell strength between cages and deep litter.…”

Section: Discussionsupporting

confidence: 82%

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Blood Plasma Mineral Profile and Qualitative Indicators of the Eggshell in Laying Hens in Different Housing Systems

2009

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The aim of this study was to compare the blood plasma mineral profile (Ca, P, K, Mg, Zn, Cu and Se) and egg-shell quality (eggshell weight, eggshell breaking strength and thickness) of laying hens housed in three different housing systems (traditional cage system, enriched cage system and deep litter system). In each housing system, 12 ISA Brown laying hens were observed during the laying period from week 22 to 75 of age. The effect (p < 0.05 and p < 0.01) of age and/or phase of the laying cycle on all mineral concentrations was determined. Eggshell breaking strength decreased (p < 0.001) with the age of birds. The results of this study indicate that the housing systems compared had no significant effect on the blood plasma mineral profile of laying hens under study and the values were within the physiological range. However, a significant effect of housing system on eggshell breaking strength and eggshell weight was found. Improved eggshell quality was obtained in most periods of the laying cycle in the enriched cage systems. Blood minerals, egg-shell quality, standard cage, enriched cage, deep litter floorPassage of the Council Directive 1999/74/EC has resulted in the replacement of traditional cages with enriched cages, litter technologies or aviaries to improve the welfare of laying hens. The shell quality remains one of the most important issues for the technology of further egg handling (Ledvinka et al. 2000). However, some authors pointed out that there are differences in eggshell quality and proportion of cracked eggs between different housing systems (Abrahamsson et al. 1995;Abrahamsson and Tauson 1997;Wall and Tauson 2002). Shell quality can be influenced by many factors including mineral nutrition. Calcium, magnesium and phosphorus are major inorganic constituents of avian eggshells (Cusack et al. 2003). Simons (1976) found small amounts of potassium, copper and zinc in the palisade layer of the eggshell. The presence of sodium, potassium, magnesium, zinc, and copper was confirmed also in the shell membranes (Wedral et al. 1974). The importance of minerals is reflected in changes of arrangement pattern of shell membrane fibres in relation to the structural composition of the eggshell, for example when using copper-and magnesium-deficient diets (Leach and Gross 1983). Traces of magnesium, potassium, copper and zinc were also found in the egg cuticle. Plasma mineral concentrations during the laying period can be influenced by many factors; such as laying rate and energy requirements (Suchý et al. 2001), partial quantitative feed restriction (Sahin and Kucuk 2001), mineral supplements (Eren et al. 2004), ambient temperature (Siegel 1995;Donoghue et al. 1990;Ching 1992;Belay and Teeter 1993; Večerek et al. 2002), production type (Suchý et al. 2004), age of hens (Cerolini et al. 1990;Gyenis et al. 2006), stress (Beisel 1982Combs and Combs 1984; Tufft and Nockles 1991;Klasing 1998), exposure to heavy metals (Zralý et al. 2008), etc.With regard to differences in eggshell quality between different ho...

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Section: Discussionsupporting

confidence: 82%

“…This was to a certain extent caused by the uniform diets for all groups of birds under study because dietary levels of macro-and microelements significantly affect plasma mineral levels (Sooncharernying and Edwards 1989;Bain 1992;Petrovič et al 2006).…”

Section: Discussionmentioning

confidence: 99%

Blood Plasma Mineral Profile and Qualitative Indicators of the Eggshell in Laying Hens in Different Housing Systems

2009

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“…They tested whole hens' eggs, compressing them between rigid, parallel platens, which caused failure by propagation of cracks from the contact points. They calculated K c using a formula previously devised by one of the authors [6]. More recently Xiao et al reported similar values, of the order of 12.6 MPa p m, in a paper investigating the effect of dietary supplements on hen egg properties [7].…”

Section: Introductionmentioning

confidence: 53%

The fracture toughness of eggshell

et al. 2016

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a b s t r a c tThe shells of avian eggs are very brittle, but how brittle? Fracture toughness, K c is a standard measure used widely to characterise engineering materials. We devised a novel way to measure K c and applied it to commercial hens' eggs, obtaining a value of 0.3 MPa p m. This value is much lower than previous published values, which we argue are incorrect and misleading. We discuss how this exceptionally low toughness value (in comparison to that of other natural materials made from calcium carbonate) has been achieved by prevention of toughening mechanisms. Eggshell has an unusual combination of mechanical properties (low fracture toughness combined with high Young's modulus), making it ideally suited as a container for the developing chick, which must be stiff and rigid but also brittle enough to be broken when required. Further testing and analysis using the Theory of Critical Distances and Weibull probability theory allowed us to describe the effects of defects of various types: cracks, holes and notches, on the strength of whole eggs. These results are of commercial importance because many eggs break prematurely as a result of microscopic defects. Statement of SignificanceThis paper presents the first accurate measurements of the fracture toughness of eggshell. These results are important because eggshell is a brittle material which fails from microscopic defects, so knowledge of the fracture toughness is essential to understand its mechanical performance. The toughness value obtained is discussed in the context of other mechanical properties, of eggshell and other natural materials. This is useful for understanding how eggshell's stiffness and toughness make it ideally suited to its purpose, and the mechanisms by which toughness is achieved. The paper also contains analysis of the effect of defect type, including cracks, notches and holes, to provide a fuller picture of defect tolerance which will be useful in the egg producing industry.

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“…Just prior to oviposition the proteinaceous cuticle is deposited onto the outermost surface of this calcified structure. The total thickness of the completed eggshell is approximately 320 μm but the main load bearing part of the shell corresponds to the combined thicknesses of the palisade, vertical crystal layer and cuticle (Bain 1992). …”

Section: Industrial Contextmentioning

confidence: 99%

The mechanics and mechanisms of failure of hens’ eggs

2006

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The mechanics and mechanisms of failure of hens' eggs have been examined experimentally under contact loading conditions relevant to industrial conditions by testing eggs of known provenance in compression between stiff platens. Deformation was modelled computationally as a Hertzian contact problem between a thin walled elastic shell and a rigid plate. Contact damage was determined by scanning electron microscopy and by optical examination of transverse sections through the shell. Small stable micro-cracks were found to initiate in the contact area before structural failure, which was characterised by the propagation of one or more macroscopic cracks. Structural failure does not correspond to crack initiation, but crack propagation. Stable micro-cracks were not detectable by routine visual inspection or acoustic resonance, and combined with inconsistent cuticle coverage these could provide a pathway for pathogens to enter the egg contents and thus compromise egg safety.

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Eggshell strength: A relationship between the mechanism of failure and the ultrastructural organisation of the mammillary layer

Cited by 74 publications

References 17 publications

Blood Plasma Mineral Profile and Qualitative Indicators of the Eggshell in Laying Hens in Different Housing Systems

Blood Plasma Mineral Profile and Qualitative Indicators of the Eggshell in Laying Hens in Different Housing Systems

The fracture toughness of eggshell

The mechanics and mechanisms of failure of hens’ eggs

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