Hatching asynchrony in avian species generally leads to a size hierarchy among siblings, favouring the first-hatched chicks. Maternally deposited hormones affect the embryo and chick's physiology and behaviour. It has been observed that progesterone, a hormone present at higher levels than other steroid hormones in egg yolks, is negatively related to body mass in embryos, chicks and adults. A d...

Bull spermatozoa were pellet frozen on dry ice in a TES buffer containing combinations of egg yolk and glycerol to determine which component of an extender afforded cryoprotection to the spermatozoa. Neither buffer nor buffer plus glycerol protected sperm cell motility in the absence of egg yolk, while sperm cells frozen in egg yolk buffer in the absence of glycerol had 24% postthaw motility (P...

Understanding reproductive performance in ecologically impoverished vs. more sustained anthropogenic habitats is critical to assess population health status and to develop land use and conservation management strategies. We compared resourcebased maternal effects, reproductive performance, and offspring quality in a model migratory passerine bird, the European starling (Sturnus vulgaris). We as...

Rice bran (RB) is a major by-product, produced from the rice milling process. This study was conducted to evaluate the performance, egg quality, and blood biochemical parameters of 288 Hy-line laying hens fed diets with rice bran and commercial microbial phytase Natuphos®5000. The experiment was a 4×2 factorial one with four RB levels (0, 5, 10, and 15%) by two phytase levels (0 and 5000 FTU/kg...

A method is described for the chromatographic separation of mixtures of egg-yolk proteins of low solubility, by using a hydrophobic column (phenyl-Sepharose) and eluting with increasing concentrations of aqueous urea at low pH. The resolving power of the method was established by tests on proteins and protein fragments of known sequence. The theoretical basis for the method remains, however, un...

This experiment was conducted, during a seven-week period to investigate, the effects of using various levels of garlic cloves and turmeric rhizome powders, on laying hens’ performance, egg quality characteristics and cholesterol content in yolk. Two hundred and sixteen, 27-weeks old Novogen white laying hens were assigned randomly into nine treatments with eight replicates of three birds each....

In this study we investigated the role of corticosterone (B) in regulating the proportion of laying females, timing of breeding, reproductive output (egg size and number), and yolk precursor levels in chronically B-treated female zebra finches (Taeniopygia guttata). Corticosterone treatment via silastic implant elevated plasma B to high physiological (stress-induced) levels (24.1 +/- 5.3 ng/ml ...

Although the particulate fraction of egg yolk (yolk granules) has attracted the attention of investigators since Miescher (1) and Hoppe-Seyler (2)) reliable information concerning the distribution of the yolk constituents between its soluble phase and the granules is lacking. Separation of both phases is difficult, owing to the high viscosity of egg yolk. For this reason, all information concer...

A study was conducted to develop a simple sequential separation protocol to separate phosvitin and IgY from egg yolk without using organic solvents. Egg yolk was diluted with 2 volumes of distilled water (DW), homogenized, and centrifuged. The precipitant was collected and homogenized with 4 volumes of 10% NaCl (wt/vol) in 0.05 N NaOH solution to extract phosvitin. The pH of the homogenate was ...