Research on eggshell structure and quality: an historical overview

Abstract

The eggshell is an important structure for two reasons. Firstly it forms an embryonic chamber for the developing chick, providing mechanical protection and a controlled gas exchange medium. Secondly it is a container for the market egg, providing protection of the contents and a unique package for a valuable food. The superficial structure of the shell has been known for over 100 years. The shell consists of 97% calcium carbonate, and this is provided to the hen in the diet. However, the chemical must be broken down in the digestive system and then re-synthesized in the shell gland to form the shell. This results in a turnover of blood Ca of ~ 100 times each 24 hours. Provision of calcium to layers has been researched at length, but the key work, conducted at Cornell University in the 1960's, showed the necessity for sources with large particle size, for example, oyster shells. Subsequent research has defined guidelines that, if correctly followed, will yield reliable and optimum eggshell quality. Breakage or cracking of eggshells in market channels is a serious concern. Cracks result from a combination of shell strength and integrity, and the extent of the "insult" received by the egg during handling. Measurement of shell strength, and assessment of "insults" is important to the poultry industry. Most recent research has identified the ultra-structure of the shell, with resulting opportunities for industrial remedies, and possible new selection criteria, to ensure maximum shell quality throughout the egg industry

Quality and mineral composition of eggs from hens supplemented with copper-lysine chelate

“…Changes that occur along with the age of the hens result from the slowing down of the mineralization process and limiting calcium and phosphorus assimilation in the feed. Proper mineralization of the shell is influenced by, among other things, structural proteins, calcium, vitamin D3, vitamin C, chlorine, magnesium, and electrolyte balance in body fluids (Hunton, 2005). Among the micro-and macroelements in the feed in terms of egg shell quality, the most important are calcium and copper.…”

Pengaruh Fortifikasi Nanopartikel Kalsium Laktat Kerabang Telur Terhadap Sifat Kimia Dan Fisik Bakso Ayam

“…Kandungan kerabang telur 97% kalsium karbonat (Hunton, 2005) dan dapat dibuat tepung kerabang telur sebagai sumber kalsium pangan yaitu sekitar 39% (Schaafsma et al, 2000). Tepung kerabang telur dapat digunakan sebagai bahan tambahan pangan sumber kalsium (Schaafsma et al, 2000;Ockerman dan Hansen, 2000) sampai level 0,4% tidak mempengaruhi palatabilitas dan kualitas pemasakan (Ockerman dan Hansen, 2000).…”

Effect of Uniformity of Eggshell Thickness on Eggshell Quality in Chickens

“…For table eggs, the eggshell is a natural packing material which can block the direct invasion of extraneous bacteria, viruses, and pathogens, reducing the likelihood of diseases caused by contaminated eggs (Nys et al, 2011). Shell breakage for any reason during the production chain will result in downgrade of eggs as well as economic losses to commercial companies (Hunton, 2005). It is important to improve eggshell quality through genetic selection to reduce eggs with inherently poor eggshell.…”