During development, the chick embryo mobilizes the calcium it needs from two extraembryonic sources, first the yolk and then the eggshell. Since previous studies have strongly suggested that vitamins D and K may regulate chick embryonic calcium metabolism, we have examined here how these vitamins might be involved in regulating the calcium mobilization processes. We used as our experimental sys...

The avian eggshell is a highly ordered calcitic bioceramic composite, with both inorganic and organic constituents. The interactions between the inorganic and organic components within the structure are poorly understood but are likely to occur at the nanometre level. Thus structural variation at this level may impinge on the overall structural integrity and mechanical performance of the eggshe...

The present study aimed at evaluating the effect of the dietary inclusion of organic trace minerals selenium and zinc on the performance and internal and external egg quality of Japanese quails submitted to heat stress. Data on egg production, feed conversion (kg feed intake/ kg eggs and dozen eggs), egg weight, egg specific gravity, eggshell thickness and weight, Haugh unit, yolk index, albume...

This study aimed to determine the mechanism by which H9N2 avian influenza virus (AIV) affects eggshell quality. Thirty-week-old specific pathogen free egg-laying hens were inoculated with the chicken-origin H9N2 AIV strain (A/Chicken/shaanxi/01/2011) or with inoculating media without virus by combined intraocular and intranasal routes. The time course for the appearance of viral antigen and tis...

Avian eggs contain all the necessary materials for embryonic development except for oxygen, which diffuses in from the environment via pores in the hard, calcified eggshell to the chorioallantoic membrane (CAM), the respiratory organ, which is rich in blood vessels. An air cell is formed at the blunt pole of the egg between the two membranes of the eggshell and enlarges during incubation due to...

This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown) were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged ind...

OBJECTIVE This study was conducted to investigate the effects of dietary detoxified Rhus verniciflua sap (RVS) on production performance, egg quality, lipid fractions of egg yolk, liver and serum, and the profile of cecal microflora in laying hens. METHODS Two hundred 52-week-old Hy-Line Brown layers were randomly divided into 4 groups with 5 replicates per group (2 hens per cage, 5 cages per...