Egg hatching has been studied in Aedes aegypti (L.) through scanning electron microscopy. The first sign of egg hatching is a small protrusion on the eggshell in the anterior pole. The larval movement provokes a crack in the eggshell with the egg buster located in the dorsal head. The egg buster provokes a small transverse fissure in the eggshell that gradually increases in the chorion. Then, t...

It was previously reported (Tuan, 1980a) that the development-specific expression of calcium transport and related functions in the chick embryonic chorioallantoic membrane (CAM) requires the continuous presence of the eggshell, the calcium source of the embryo. To further understand the mechanism of action of the eggshell on the CAM functions, this study reports the effects of eggshell supplem...

review of eggshell pigmentation. Worlds Poult. Sci. J. 43, 238–246. 17. Collias, E.C. (1993). Inheritance of eggcolor polymorphism in the village weaver (Ploceus-Cucullatus). Auk 110, 683–692. 18. Hutt, F.B. (1949). Genetics of the Fowl (New York: McGraw-Hill). 19. Miksik, I., Holan, V., and Deyl, Z. (1996). Avian eggshell pigments and their variability. Comp. Biochem. Physiol. BBioche. Mol. Bi...

This study was conducted to compare ileal digestibility of calcium, dry matter and ash, growth performance, gut characteristics, bone parameters and retention of calcium in broiler chickens fed diets containing different calcium sources. A total of 96 commercial Ross 308 broiler chickens were allocated to three experimental diets. The experimental diets included a diet containing inorganic calc...

The protein composition of the insoluble avian eggshell matrix was studied. The determination of these proteins insoluble in water (EDTA-insoluble) was carried out using enzymatic cleavage followed by a high-performance liquid chromatography-mass spectrometry method. The influence of various enzymes on the protein splitting also was studied. The distribution of proteins depends on the type of l...

Eggshell penetration by pathogens is considered a potential route for their transmission in poultry flocks. Additionally, in case of zoonotic pathogens, contact with infected eggs or their consumption can result in human infection. Chlamydia psittaci is a zoonotic bacterium that causes a respiratory disease in poultry and humans. In this study, we provide an experimental evidence for eggshell p...

A high-~rforman~e liquid chromato~aphy method was used for the deter~ation of the eggshell pigment constituent. Using this method, the content proto~rphyrin IX in seven bird species was quantified. It was found that this compound is most abundant in the eggs of the blackbird (65.55 nmol per egg), but when the amount is related to the eggshell mass, then the greatest amount is in the egg of the ...

Novel and traditional eggshell quality measurements were made from up to 2000 commercial pedigree hens for a candidate gene association analysis with organic eggshell matrix genes: ovocleidin-116, osteopontin (SPP1), ovocalyxin-32 (RARRES1), ovotransferrin (LTF), ovalbumin and ovocalyxin-36, as well as key genes in the maintenance and function of the shell gland [estrogen receptor (ESR1) and ca...

In metazoans, fertilization triggers the assembly of an extracellular coat that constitutes the interface between the embryo and its environment. In nematodes, this coat is the eggshell, which provides mechanical rigidity, prevents polyspermy, and is impermeable to small molecules. Using immunoelectron microscopy, we found that the Caenorhabditis elegans eggshell was composed of an outer vitell...

The Japanese quail lays eggs with colourful and patterned shells which make the eggshell colour difficult to classify. In this study, the method of measuring colour of patchy eggs using image analyses and its power to discriminate among individual variation were established. Estimated repeatability for egg colour and proportion of patterned areas was high (>0.58), suggesting intermedíate or hig...