Ultrastructural characteristics of ostrich eggshell: outer shell membrane and the calcified layers

Richards, P.D.G.; Richards, Penelope; Lee, M.E.

doi:10.4102/jsava.v71i2.687

Cited by 15 publications

(7 citation statements)

References 20 publications

(33 reference statements)

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“…In the industry it is believed that higher levels of calcium in the feed will result in stronger eggshells and increase the occurrence of DIS eggs (Richards et al, 2000). In this study, no effect of a higher calcium level in the feed was recorded on the occurrence of DIS eggs, or the shell break strength.…”

Section: Resultscontrasting

confidence: 45%

The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches

Brand

Tesselaar²,

Hoffman³

et al. 2015

SA J. An. Sci.

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Earlier studies on breeding birds indicated no effect of dietary energy-content on feed intake. This observation is contradictory to results for other animals and/or poultry where feed intake decreases with an increase in dietary energy level. Literature revealed that a lack of certain nutrients may cause animals to consume more feed than necessary to satisfy their nutrient requirements for these limiting nutrients. In this study eight diet groups were evaluated. A standard commercial diet plus one of the following supplements: (i) Standard diet without a vitamin and mineral premix pack (control diet), (ii) with a normal premix pack, (iii) with normal vitamin and 2 x trace elements (M x 2), (iv) with normal trace elements and 2 x vitamins, (v) with a normal premix pack and limestone added as calcium source; (vi) with a normal premix pack and monocalcium phosphate added as phosphorus source, (vii) with a normal premix pack and soybean oilcake added as crude protein source, (viii) with a normal premix pack and linseed added as a fatty acid source. Significant differences were recorded in the quantity of feed ingested by birds between the diet with surplus minerals (M x 2) (Group 3) (2.3 ± 0.3 kg/bird/day), the diet with no vitamins and minerals added (Group 1) (2.7 ± 0.3 kg/bird/day) and the diet with added fatty acids in the form of linseed (Group 5) (2.9 ± 0.5 kg/bird/day). This indicates the possibility that ostriches may adjust feed intake to satisfy their mineral requirements. No statistically significant relationship was found between the thickness and strength of the shell. Significant differences in shell strength (mean value of 154.7, 109.9, 140.4, 142.7, 153.0, 143.4, 138.4 and 151.1 N/cm2, respectively) were found between all treatments, but no specific pattern could be identified. Results further revealed no effect of dietary treatment on egg production, dead-in-shell eggs (DIS), infertile eggs or chick production. Further experiments that include certain dietary treatments during the five months rest period are currently being done to quantify the effect of the addition of minerals and vitamins during this period on the production of breeding ostriches.Keywords: Eggshell strength; feed intake, minerals, vitamins

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Section: Resultscontrasting

confidence: 45%

The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches

Brand

Tesselaar²,

Hoffman³

et al. 2015

SA J. An. Sci.

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“…Ostrich-egg morphology consists of an external surface crystal layer; a palisade layer, which comprises most of the shell thickness; a cone layer towards the interior surface; and an organic membrane that covers the inner surface itself (Figure 4). Texier et al (2010) have drawn attention to three factors that significantly influence the morphology of decorative features on ancient ostrich eggshell: The heterogeneous orientation of the crystalline calcite that makes up 96 per cent of the structure (Richards et al 2000; Feng et al 2001). The three different layers in ostrich eggshell, which vary in structure and in thickness and can be affected by thermal changes (Heredia et al 2005).…”

Section: Resultsmentioning

confidence: 99%

“…1) The heterogeneous orientation of the crystalline calcite that makes up 96 per cent of the structure (Richards et al 2000;Feng et al 2001).…”

Section: How Were Eggs Decorated?mentioning

confidence: 99%

The origins of decorated ostrich eggs in the ancient Mediterranean and Middle East

et al. 2020

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“…The Ca is mobilized first from the yolk and then from the eggshell (Johnston & Comar , Tuan & Ono , Solomon ), which typically consists of a shell membrane and three calcified layers (Solomon 1991, Mikhailov , Richards et al . , Nys et al . ).…”

mentioning

confidence: 99%

The effect of embryonic development on metal and calcium content in eggs and eggshells in a small passerine

Orłowski

Hałupka

Pokorny

et al. 2015

Ibis

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Published information relating to changes in the chemical element content of avian eggs caused by embryonic development is extremely scarce, although it may be crucial for understanding both the presence of anthropogenic pollutants as well as physiological levels of micronutrients. We assessed the variation in concentrations of calcium (Ca) and magnesium (Mg) and nine trace elements: seven essential (chromium (Cr), copper (Cu), nickel (Ni), manganese (Mn), iron (Fe), cobalt (Co) and zinc (Zn)) and two non-essential (lead (Pb) and cadmium (Cd)) in shells and contents (both egg yolk and egg white) of embryonated and non-embryonated eggs. We investigated the eggs of the Eurasian Reed Warbler Acrocephalus scirpaceus, a large proportion of whose eggs are infertile in our study population (almost 43% of clutches contain unhatched eggs) as well as significant embryo-induced eggshell thinning at the equator of embryonated eggs. We found significantly higher concentrations (≥ 22.7%) of all the focal elements in the contents of embryonated eggs in comparison with non-embryonated eggs, and a very pronounced one for Ca (nearly twice as high). The shells of embryonated eggs contained significantly higher concentrations of Zn (104.1%), Fe (56.5%), Pb (32.8%) and Cu (28.0%) but significantly lower ones of Co (8.9%) and Ca (9.3%) than the shells of non-embryonated eggs. The simultaneous higher concentrations of all elements in the content of thinnershelled embryonated eggs suggest the parallel transfer of these elements along with Ca resorption from the shell into the egg interior during embryo formation. The higher concentration of most elements in the thinner shells of embryonated eggs may be indicative of the maternal deposition of some of these elements in a shell layer not subject to embryonic depletion, or in the eggshell membrane. Our results highlight the need for the careful selection of egg samples, which should differentiate between embryonated and non-embryonated eggs in the analytical treatment of eggs and eggshells.

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Ultrastructural characteristics of ostrich eggshell: outer shell membrane and the calcified layers

Cited by 15 publications

References 20 publications

The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches

The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches

The origins of decorated ostrich eggs in the ancient Mediterranean and Middle East

The effect of embryonic development on metal and calcium content in eggs and eggshells in a small passerine

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