We have recently established a unique in vitro experimental model for mitochondrion-rich cell (MRC) research, a ;yolk-ball' incubation system, in which the yolk sac is separated from the embryonic body of Mozambique tilapia embryos and subjected to in vitro incubation. To evaluate the ion-transporting property of the yolk balls, we examined Cl- content and turnover in yolk balls incubated in fr...

abstract  introduction: this experiment was conducted to study the effects of different levels of flaxseed (0, 5, 10 and 15% of diet) and copper (in the form of cupric sulfate pentahydrate, 0 and 250 ppm of diet) on fatty acids and cholesterol in egg yolk of laying hens. methods: a total of 128 white leghorn layers aged 50 weeks were used in a factorial design and randomly assigned to 8 treatme...

one-hundred-sixty-eight 28-wk-old hy-line layers (w-36) were used to evaluate the effect of different levels of linseed (ls) and safflower seed (ss) on antibody titter, blood and yolk cholesterol, yolk fatty acid content and the ratio of omega-6/ omega-3. hens were randomly assaigned in a compeletly randomised design each 3 replicates of 8 hens. they were fed diets contained 0, 4, 7 and 10% ls ...

Despite the strong interest in hormone-mediated maternal effects two key questions concerning their mechanisms are as yet unanswered: First, whether the deposition of hormones in the egg yolk is coupled with the levels of these hormones in the maternal circulation, and second, whether epigenetic changes as induced by embryonic exposure to maternal yolk hormones impinge on yolk hormone depositio...

The external dimensions, weight and contents (yolk, albumen, shell) of Double Yolked (DY) and Single Yolked (SY) eggs of the duck (Anas platyrhynchos domesticus) were measured and compared. The yolks in DY eggs did not differ in weight (p = 0.144), although each double yolk was significantly lighter than the yolk of a SY egg (p<0.001). DY albumen weight was below that expected of a SY egg of co...

The murine yolk sac, being the first site of embryonic blood cell production, has long been theorized to contain the migrating hematopoietic stem cells (HSC) that seed the liver and initiate hematopoiesis on day 10.0 postcoitus (pc). However, it remains controversial whether yolk sac cells isolated before day 11.0 pc possess any long-term repopulating HSC activity upon transplantation into adul...

Refrigeration to limit bacterial multiplication is a critical aspect of efforts to control the transmission of Salmonella enterica serovar Enteritidis (SE) to consumers of contaminated eggs. Although the nutrient-rich yolk interior is an uncommon location for SE contamination in freshly laid, naturally contaminated eggs, migration across the vitelline membrane could lead to rapid bacterial mult...

The present studies were performed to further characterize a mouse yolk sac protein which is similar or identical to the vitamin D-dependent intestinal calcium-binding protein (CaBP). Yolk sac protein and purified rat intestinal CaBP displayed full identity upon immunodiffusion (Ouchterlony) using antiserum to the rat intestinal CaBP. Immunoreactive CaBP in yolk sac homogenates eluted from gel ...

The mechanisms involved in the induction of yolk sac mesoderm into blood islands and the role of visceral endoderm and mesoderm cells in regulating the restricted differentiation and proliferation of hematopoietic cells in the yolk sac remain largely unexplored. To better define the role of murine yolk sac microenvironment cells in supporting hematopoiesis, we established cell lines from day-9....

The yolk, defined by McKelvey as the smallest ball intersecting all median hyperplanes, is a key concept in the Euclidean spatial model of voting. Koehler conjectured that the yolk radius of a random sample from a uniform distribution on a square tends to zero. The following sharper and more general results are proved here: Let the population be a random sample from a probability measure μ on <...