A total number of  5520 female and  480 male breeders (Arbor Acres plus) at 42wks of age  were used in a 10-week-trial to investigate the effect of an enzyme complex on  the quality  and quantity of egg production as well as hatchability of broiler breeders fed a corn-soybean meal diet. There were two dietary treatment groups: a control group fed on a corn-soybean based diet, and the multi-enzy...

High ambient temperature is a major factor for diminishing reproductive performance of broiler parent stocks. Homozygous naked neck (NaNa) broilers, which possess a higher adaptation to heat due to a reduction of feather coverage, exhibited higher growth rates and meat yield. This study was conducted to investigate the influence of genotype x temperature interactions on the reproduction traits ...

This study was conducted to determine the effect of incubation relative humidity (RH) from 14 to 24 d of incubation during 3 parental ages on hatchability and posthatching growth of Pekin ducklings. Egg production was divided into 3 age groups (25-35, 36-55, and 56-65 wk). A total of 21,600 hatching eggs was subjected to 55, 60, 65, and 70% RH from 14 to 24 d, whereas standard conditions were u...

Two peaks of embryo mortality have been identified during incubation of chicken eggs (the first and the final phases of incubation), and both are linked to egg turning. Turning in the first week enables proper formation of extra-embryonic membrane and in the final week avoids embryo malpositioning. The hatchability of the eggs, however, may depend on physiological parameters (e.g., hormone leve...

When domestic fowl were maintained under constant incandescent illumination from time of hatching, the rate of egg production was similar to that of control birds on a diurnal schedule. Hatchability offertile eggs produced by such hens was found to be unaffected by lighting treatment of the parents. Fertility was, however, markedly impaired in the males reared under continuous light. Artificial...

Environmental contaminants may have adverse effects on avian reproduction and may be contributing to declines of avian species nesting along the southern California Coast. Examples of impaired reproduction caused by organochlorine pesticides, PCBs, and elements such as mercury (Hg) and selenium (Se) include delayed ovulation, reduced egg production, defective eggshells, decreased hatchability, ...

Geologic and allozyme evidence suggests that threespine sticklebacks (Gasterosteus aculeatus complex) in low-lying southwestern British Columbia lakes were founded during two incursions of marine sticklebacks after the retreat of the Pleistocene glaciers (the double-invasion hypothesis). We used the salinity tolerance of embryos, measured as hatchability in salt water, to establish the relative...

background: in the current iranian poultry industry, antibiotics are the most frequently used additive in poultry feeds to increase productivity. the negative effects on human health, resulting from the consumption of chicken whose feeds contain antibiotics, makes finding an appropriate alternative of great importance. as a result of their nature, herbal extracts could be specifically considere...

Replicates of the two isogenic laboratory strains of Drosophila melanogaster, 2b and Harwich, contain different average transposable element (TE) copy numbers in the same genetic background. These lines were used to analyze the correlation between TE copy number and fitness. Assuming a weak deleterious effect of each TE insertion, a decrease in fitness is expected with an increase in genomic TE...