Embryos of oviparous Reptilia (=turtles, lepidosaurs, crocodilians and birds) extract calcium for growth and development from reserves in the yolk and eggshell. Yolk provides most of the calcium to embryos of lizards and snakes. In contrast, the eggshell supplies most of the calcium for embryonic development of turtles, crocodilians and birds. The yolk sac and chorioallantoic membrane of birds ...

This study attempted to clarify the difference in eggshell pigmentation between blue-shelled ducks (BSD) and whiteshelled ducks (WSD). The eggshell pigmentation deposition process is discussed. Ultraviolet spectro-photometer and HPLC were used to determine the biliverdin concentration in the shell gland, uterus liquid and eggshell at 6, 12, 18, 20, 23.5 h post-oviposition. The biliverdin concen...

A mechanism for eggshell production in Schistosoma mansoni has been proposed (Wells & Cordingley, 1991), and suggests that the release of eggshell protein globules from the vitelline cells occurs under alkaline conditions within the ootype followed by their subsequent fusion to form the eggshell. Fusion and tanning of these components produces eggshell which autofluoresces. The present study wa...

We conducted an experiment to evaluate the potential for dietary 1,4-diaminobutane (putrescine) to promote eggshell quality and overall laying hen performance. A total of 128, 60-wk-old Barred Rock hens were fed a corn and soybean meal-based layer diet supplemented with 0.0 (control), 0.2, 0.4, and 0.6% free base 1,4-diaminobutane for 4 wk. The feeding of supplemental putrescine decreased feed ...

Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully char...

The first clutch of Mesozoic eggs containing embryos was collected more than twenty years ago from the Rooidraai locality in Golden Gate Highlands Park, South Africa. The Elliot Formation crops out throughout the area, and although the sediments exposed at Rooidraai were once thought to be Late Triassic in age, they are now regarded as Early Jurassic. The Elliot Formation preserves a rich terre...

AbstractESW as a natural byproduct, although non-hazardous and contains calcium, magnesium carbonate and protein, is commonly disposed in landfills without any pretreatment because it was traditionally useless. In this regards, we wish to report the synthesis of a novel CaO/Ca2Fe2O5 nanocomposite based on ESW. At the first, eggshell (ES) nanopowder was prepared by ball-milling. Then, the ...

The depletion of resources and increase in demand for fossil fuel raise concerns as it is natural non-renewable. Therefore, will cause limitation on its availability continuous reduction. This issue has led to the search more economic, sustainable, environmentally friendly alternatives which biodiesel. major drawback that reduces possibility biodiesel commercialization high cost oil feedstock c...

The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (he...

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them viable option achieving sustainability in construction sector. This study addresses utilisation two agro-wastes, i.e., eggshell walnut shell, manufacture unburnt clay blocks. The experiments were carried out on thr...