Fecundity is an important component of individual fitness and has major consequences on population dynamics. Despite this, the influence of individual genetic variability on egg production traits is poorly known. Here, we use two microsatellite-based measures, homozygosity by loci and internal relatedness, to analyse the influence of female genotypic variation at 11 highly variable microsatelli...

The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the ...

Egg productivity is the most important economic trait in egglaying poultry. Endocrine and environmental factors such as length of photoperiod and feeding allowance can influence egg production [1]. However, a genetic factor would be a prerequisite. Egg production is a polygenic inheritance trait with low to moderate heritability depending on the period involved, a major opportunity for improvem...

This study was carried out to investigate the effect of two housing systems on external and internal egg characteristics of a commercial laying bird. Two hundred and eighty pullet of Nera layers were divided into two even group kept in different housing systems (deep litter vs cage). External and internal egg quality traits were examined at 26, 30, 34 and 38wk. Data were then collected on egg w...

The study was conducted to determine the effect of varying protein levels and preservation method on internal egg qualities of Japanese quails. A total of 180 birds were randomly allotted into three dietary treatments in a completely randomized design (CRD) replicated six times. A factorial arrangement of 3x4x4 which involves 3 protein levels, 4 storage method and 4 time intervals was designed ...

Egg size is a critical life-history trait because it can profoundly influence offspring fitness and the number of offspring that can be produced. Recently, interest has grown in how egg size influences fertilization rate and in turn how sperm availability might influence the evolution of egg size among broadcast-spawning marine invertebrates. In this article I review the empirical evidence on t...

Genetic correlation coefficients between egg quality traits were studied using fiftysix harco pullets raised under standard management practices. The estimates were carried out at 22-week, 26-week, 30-week and 32-week of age. Egg quality traits studied include egg weight (EW), shell thickness (ST), haugh unit (HU), yolk index (YI) and shape index (SI). Zero to slight negative correlation coeffi...

This research was carried out to compare the productivity performance of three lines local quail. The results showed a significant superiority in daily gain weight (3.76 g/day/quail) and marketing (167.2 g/quail) for brown quail over other colors. Also, differences were found dressing ratio between males (67.8%) females (65.76%). As egg production quail, it desert colors number eggs produced, a...

Complete genome resequencing of populations holds great promise in deconstructing complex polygenic traits to elucidate molecular and developmental mechanisms of adaptation. Egg size is a classic adaptive trait in insects, birds, and other taxa, but its highly polygenic architecture has prevented high-resolution genetic analysis. We used replicated experimental evolution in Drosophila melanogas...