this experiment was carried out to study the effects of different levels of canola meal of different fat sources on the egg quality, performance as well egg yolk cholesterol during the first 12 weeks of age in laying hens (hy-line w-36). throughout the experiment a total of 432 hens were employed in a completely randomized design in a factorial arrangement of 3×4, with three levels of canola me...

A total number of 225 Fayoumi hens 34 weeks old , were used in this experiment to study the effect of supplementing layer diet with 0.2% casein (c) with or without 0.015% iodine as 0.02% potassium iodide (KI) in drinking water on the performance and egg quality. The experiment continued for 90 days. Birds were randomly divided into three groups , each group contained 3 replicates of 25 each . B...

the objective of present study was to determine the effects of β-mannanase-based enzyme (hemicell®) on productive performance and egg quality in diets containing graded levels of whole date waste (wdw) fed to laying hens. a total of 336 hy-line leghorn hens after production peak were randomly divided into 56 cages. eight iso-energetic and iso-nitrogenous experimental diets in a 4 × 2 factorial ...

Availability of the complete genome sequence as well as high-density SNP genotyping platforms allows genome-wide association studies (GWAS) in chickens. A high-density SNP array containing 57,636 markers was employed herein to identify associated variants underlying egg production and quality traits within two lines of chickens, i.e., White Leghorn and brown-egg dwarf layers. For each individua...

Hatchability is a complex age dependent trait. It comprises of several sub-traits which are susceptible to genetic and environmental factors arising from various sources. This review examines the genetic basis of egg production, fertility and egg quality traits and how these relate with hatchability. We suggest that both sire and dam genetic components are important in overall hatchability most...

CTSD (Cathepsin D) is a key enzyme in yolk formation, and it primarily affects egg yolk weight and egg weight. However, recent research has mostly focused on the genomic structure of the CTSD gene and the enzyme's role in pathology, and less is known about the enzyme's functions in chickens. In this paper, the correlations between CTSD polymorphisms and egg quality traits were analyzed in local...

Three White Leghorn strains, their two-way crosses, and two commercial lines were used to study the effects of aging on several parameters related to performance of fitness and nonfitness traits during the first laying cycle of hens housed three per cage. Egg number of the survivors (EPF) and egg number including mortality and morbidity (EPM) were divided into 12 periods of 28 d each, starting ...

A mapping population segregating for egg quality traits was created by a line cross between two egg layer lines and screened by a genome scan. The F2 generation consisted of 307 hens, which were scored for egg quality and production traits. The mapping population was genotyped for 99 microsatellite loci, spanning nine macrochromosomes and five small linkage groups. The linkage maps were used in...