The evolution of brood parasitism has long attracted considerable attention among behavioural ecologists, especially in the common cuckoo system. Common cuckoos (Cuculus canorus) are obligatory brood parasites, laying eggs in nests of passerines and specializing on specific host species. Specialized races of cuckoos are genetically distinct. Often in a given area, cuckoos encounter multiple hos...

Broken and weak bones of laying hens are major welfare concerns in the table egg industry. Bone quality at the end of lay of brown- (Shaver 579) and white-(Shaver 2000) egg strains were compared. Prior to the start of the experiment, the hens had been housed in laying hen cages (2/cage). At 423 d of age (60 wk + 3 d), 24 hens of each strain were selected and individually caged, and egg producti...

Pectoralis major muscle morphology was studied in both sexes of a turkey line (E) selected long-term for increased egg production and its randombred control (RBC1) from 25 d of incubation through 20 wk posthatch. Pectoralis major muscle samples from 10 individuals from each line-sex-age subgroup were obtained in a manner to prevent contraction. The muscle samples were dehydrated, cleared, embed...

Breast muscle morphology was studied at 8 and 16 wk of age in a line (E) selected over 44 generations for increased egg production and its randombred control line (RBC1). A sample of 20 birds per sex-line-age subgroup was killed with restraint to prevent flapping of the wings. The skin was removed from the breast region, and a sample of breast muscle was obtained in a manner to prevent contract...

In this study, spermatheca and eggs of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae were examined by light microscope SEM. The have ~1.30 mm length 0.94 width. Newly laid turn from white to yellow as soon embryonic differentiation. P. egg surface shows polygonal (usually hexagonal pentagonal) shapes. pipe shaped 6-7 micropylar projections. egg-burster which is a dark T-shaped or triangular p...

________________________________________________________________________________ Abstract The effect of photostimulation of male broiler breeders (n = 144) to different photoperiods (8-h control and 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 14 and 18 h) applied at 20 weeks of age, on age at first semen production, testis weights, as predicted by comb area, and semen characteristics at the repor...

Ooplasmic transplantation aimed at restoring normal growth in developmentally compromised oocytes and embryos was evaluated in seven couples (eight cycles) with multiple implantation failures. Two approaches were investigated to transfer ooplasm from donor eggs at metaphase II (MII) stage into patient MII eggs: (i) electrofusion of a ooplasmic donor fragment into each patient egg (three cycles)...

We have previously shown that Xenopus oocytes, eggs, and early embryos contain lamins LII and LIII, and that portions of each are associated with distinct egg vesicle populations. We now report that a lamin similar or identical to the B-type lamin LI is also present in oocyte nuclei and in egg extracts. We have quantitated the three B-type lamins per oocyte nucleus, and have calculated relative...