The present study was conducted to investigate the effects of different levels of pomegranate by- product (PBP) on performance, egg quality and blood parameters in laying hens. A total of 144 Bobze layer hens from 44 to 56 weeks during 12 weeks were randomly assigned into 4 treatments including 0 (control, corn and soy bean meal), 4, 8 and 12% of PBP, with 4 replicates and 9 layers in each. Res...

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...

Drosophila melanogaster females are highly selective about the chemosensory quality of their egg-laying sites, an important trait that promotes the survival and fitness of their offspring. How egg-laying females respond to UV light is not known, however. UV is a well-documented phototactic cue for adult Drosophila, but it is an aversive cue for larvae. Here, we show that female flies exhibit UV...

Reproduction is influenced by many external factors. For egg laying of pond snails, one important trigger is the transfer from dirty, oxygen-poor water to clean, oxygen-rich water. This response is due to the combined effects of elevated oxygen level, chemical water composition and clean substrate. Whether this clean-water stimulus (CWS) resembles the natural egg-laying process has remained unt...

Shell quality has been identified as a heritable trait that can be manipulated by genetic selection. Previous research has concluded that many methods of determining shell quality produce variable results. With the development of newer, more precise measuring technologies, shell strength can now be assessed in a consistent, objective fashion. A research project was conducted to determine what r...

The furnished cage is a new housing system for layers. A current trend in furnished cage design is to increase group size and replace the litter box with a mat provided with litter. An experiment was set up to determine the effects of group size and litter provision on laying performance and egg quality of beak-trimmed ISA Brown hens housed in large furnished cages with more than 12 hens. Six t...