Egg-laying behavior in the nematode Caenorhabditis elegans involves fluctuation between alternative behavioral states: an inactive state, during which eggs are retained in the uterus, and an active state, during which eggs are laid in bursts. We have found that the flp-1 gene, which encodes a group of structurally related neuropeptides, functions specifically to promote the switch from the inac...

Prostaglandin F (PGF) concentrations in the serum of laying and nonlaying hens and of cocks at various times during a day were measured by radioimmunoassay. The serum concentration of PGF was higher in laying hens than in nonlaying hens or cocks without regard to time of day. In all birds, the concentration showed a peak at 2 h after onset of light (0700 h). In laying hens on the day of laying ...

Pheasant eggs evaluated in the first period of egg-laying did not differ significantly in their weight and shape index and the values of both traits were, respectively, 30.7 to 32.2 g and 76.1 to 78.1%. Over the laying season the thickness of the shell decreased and its capacity for deformation and crush strength were greatest at the end of the laying season. The share of yolk in the egg was hi...

The authors report the results of their study aimed at investigating the consequence of targeted ablation of ventral lateral neurons (LN(v)s--neurons regulating eclosion and locomotor activity rhythms) and genetic disruption of pigment-dispersing factor (PDF--an important output of circadian clocks) on the egg-laying rhythm of Drosophila melanogaster. The results clearly suggest that genetic ab...

This study was aimed to determine abundance and body distribution of PRM in laying hens of Arak. A total of 1400 laying hens were randomly examined from January to June 2008. Of those, 26 (92.86%) layer farms were found to be infested with Dermanyssus gallinae (39.3%). There was significant association between prevalence and climatic conditions of the region. The most common predilection site o...

The process of creating promising technical means is always based on the results previous studies devoted to definition and justification requirements for samples being developed. use modern methods simulation (computer) modeling at stage research works helps analyze many available options implementation developed systems, assess degree load their individual elements, form reasonable proposals ...

this study was performed to determine the incidence and anatomo-pathological aspects of the reproductive system tumors in commercial laying hens. post mortem examination of 1041 laying hens revealed neoplasms of the ovaries and the oviduct in 52 (4.99%) cases. from these, ovarian adenocarcinoma was found in 14 cases, granulosa cell tumor in 7 cases, theca cell tumor in 1 case and marek's diseas...

this experiment was conducted to evaluate the effects of using of zizaphora (thymyus valgaris), peppermint (lamiaceae menthapiperita), menta pulagum (oreganum valgare) medicinal plants on performance, egg quality, blood and immunity parameters of laying hens. this experiment was conducted in a completely randomized design with 288 of hy line (w-36) laying hens in 8 treatments and 3 replicates (...