Micro‐Focus X‐Ray Tomography Study of the Microstructure and Morphometry of the Eggshell of Ostriches (Struthio Camerus)

Abstract

In ostrich husbandry, economic losses have mainly been attributed to low hatchability of eggs, which has mostly been attributed to the structure of the eggshell. The main aim of this study was to investigate the morphology and the morphometry of the ostrich eggshell using micro-focus X-ray computer tomography and scanning electron microscopy. The mean weight and volume of the eggs were 1,312 6 56SE g and 1,333 6 44SE cm 3 , respectively. The mean thickness and the mean surface area of the eggshell was 1.83 6 0.10SE mm and 619 6 15SE cm 2 respectively and the mean total number of pores in the shell was 40,596 6 1832SE. No significant correlations were found between the thickness of the shell and the weight of the eggs, the volume of the egg and the thickness of the shell, the diameter of the pores and the number of pores, the volume of the pores and the number of pores or the surface area of the pores and the number of pores. The mean diameters of the pores on the blunt (air cell) 2 (0.02 6 0.04SE mm) and the sharp (0.26 6 0.36SE mm) parts of the eggshell were significantly different (P 5 0.0001) while the mean volumes and the surface areas of the pores in these parts were not significantly different (P 5 0.203 and P 5 0.089, respectively). The sizes of the pores differed in different parts of the eggshell, which consisted mainly of tightly arranged mammillary cones that that fused to the palisade columns. The external surface of the ostrich eggshell was covered by a cuticle.

Shifts in eggshell thickness are related to changes in locomotor ecology in dinosaurs

“…1996; Willoughby et al. 2016). This variety in pore structure and nesting behavior among paleognaths is likely independent of eggshell thickness (Tyler and Simkiss 1959), and further analyses of paleognath eggshell microstructure will be required to understand how these individual constraints may have affected their egg characteristics and reproductive strategies.…”

The eggshell structure in apteryx; form, function, and adaptation

“…Nevertheless, the function of these types of pores is still not clear. Similar pores that do not transverse the eggshells have been observed in the eggs of Ostriches, another member of the monophyletic group known as Ratites (Maina, 2017; Willoughby et al., 2016). We suggest that future studies should examine the possible role of these partial pores on the strength of the eggshell as well as how these partial pores affect water vapor conductance.…”

“…Nevertheless, the function of these types of pores is still not clear. Similar pores that do not transverse the eggshells have been observed in the eggs of Ostriches, another member of the TA B L E 7 Calculated eggshell thinning based on the water vapor conductance of an infertile egg (Calder, 1978) and the water vapor conductance of artificially incubated eggs during the last 26 days of incubation (N = 18) monophyletic group known as Ratites (Maina, 2017;Willoughby et al, 2016). We suggest that future studies should examine the possible role of these partial pores on the strength of the eggshell as well as how these partial pores affect water vapor conductance.…”

Evaluation of Calcium Carbonate Content in Eggshells of Avian, Turtle, Snail, and Ostrich Using Chemical Analysis and Scanning Electron Microscopy

“…The structure of the avian shells has mainly been investigated with imaging methods e.i. X-ray microscopy (XRM) [7], scanning electron microscopy (SEM) [8], transmission electron microscopy (TEM) [9] and optical light microscopy (LM) [10]. Despite the widely recognized importance of the chemical identification of various avian eggshell pigments and the detection of the pesticides on shells using various imaging methods, researching the morphology of the calcareous layer of eggshells as well as calcium carbonate content between different eggshells is an important step towards the better understanding of detection and characterization of shell components of avian eggs.…”