the goal of this experiment was to investigating of effects of different levels of nano chromium (n-cr) in diet on egg quality and blood chromium content of japanese quail. two hundred and forty laying japanese quail (45 day old) were randomly distributed to 20 experimental unit with 12 birds in cage pens of 40 × 80 cm. experimental treatments include: 1) control national research council (nrc,...

Understanding how genes shape phenotypes is essential to assess the evolutionary potential of a trait. Identifying the genes underlying quantitative behavioral or life-history traits has, however, proven to be a major challenge. The majority of these traits are phenotypically plastic and different parts of the genome can be involved in shaping the trait under different environmental conditions....

Rejection of the parasitic egg is the most important defence of hosts against brood parasites. However, this response is variable among and within species, and egg discrimination is not always followed by egg rejection. Low risk of parasitism and high risk of rejection costs may lead to the acceptance of the parasitic egg even if it has been previously recognized. The main aim of this paper is ...

Eggshell quality is the main trait to assess egg quality. Marker assisted selection can be used to improve this trait. During eggshell formation, a mass of inorganic minerals is deposited. The Sodium Channel (SCNN1) gene family plays an essential role in cation transportation and SCNN1g is a member of this gene family. The objective of this study was to estimate the frequency of SCNN1g gene var...

The effects of dietary supplementation with phytase and 25-hydroxycholecalciferol on the performance characteristics of commercial layers that were inoculated prelay (12 wk of age) or at the onset of lay (22 wk of age) with F-strain Mycoplasma gallisepticum were assessed. Experimental layer diets, which included a basal control diet or the same diet supplemented with 0.025% phytase and 25-hydro...

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...

Interactions between parasitic cuckoos and their songbird hosts form a classical reciprocal "arms race," and are an excellent model for understanding the process of coevolution. Changes in host egg coloration via the evolution of interclutch variation in egg color or intraclutch consistency in egg color are hypothesized counter adaptations that facilitate egg recognition and thus limit brood pa...

A morphological study with the use of scanning electron microscope of 67 species of Iberian Lycaenidae is presented. The study covers all the genera present in the area and shows an extraordinary variation in chorionic characters that allows egg diagnosis for most species. A morphometric study showed that the eggs from the sample have sizes that are correlated with adult size, but some species ...

A N I M A L breeders often select the extreme individuals in a population. This may conflict with natural selection for reproductive fitness. For example, chickens with intermediate body weights and egg weights usually have the highest hatchability. LATTER and ROBERTSON ( 1962) hypothesized that the decline in fitness with selection for a metric trait is a consequence of gene frequency changes ...

The difference between progeny from selected and unselected parents (T) was experimentally partitioned into net genetic change (G(A)), temporary favorable epistatic combinations (G(EP)) and egg-transmitted maternal environment (M) in two strains of Leghorns selected over 14 years for early pure-strain egg production. Differences among progeny from selected sires and dams, selected sires only, s...