Megapodes are exceptional among birds because they use external heat sources for incubating their eggs. In Australian brush-turkeys (Alectura lathami), this source is the heat produced by microbial decomposition in mounds of leaf litter. A recent laboratory study showed that artificial incubation of eggs at different temperatures affects the sex ratio of brush-turkey hatchlings. Here, this phen...

Investigations in our laboratory have established that infection with SalmoneUa pulorum strain CDC 3522/51 results in a decrease in arginine, methionine, glycine and tryptophan in the blood and liver of 1to 3-day old White Leghorn cockerels (Ross et al., 1955a). Subsequent experiments revealed that the administration of arginine within 24 hr following infection produced a marked increase in sur...

An experiment was conducted to study the effects of different eggshell temperature (EST) profiles during incubation on embryo mortality, hatchability, and embryo development. Furthermore, chicks from different EST profiles were reared under low and high housing temperatures to investigate subsequent posthatch growth and rectal temperature. Two batches of eggs were used in this experiment. Hatch...

An experiment was conducted to study the effect of egg size on embryo development, heat production, and energy partitioning between egg and hatchling. Small (56.1 +/- 0.12 g SEM) and large (70.0 +/- 0.11 g SEM) hatching eggs were incubated in climate respiration chambers, and eggshell temperature was maintained constant at 37.8 degrees C in both egg weight classes by adjusting machine temperatu...

Kanamycin, penicillin, and streptomycin were injected individually into air cells of newly set chicken and turkey hatching eggs, and assay was made throughout the incubation period to determine the location, potency, and duration of efficacy. By 24 hours, each antibiotic had diffused throughout the albumen. By six days, penicillin residues could not be detected, whereas kanamycin or streptomyci...

The black-chinned tilapia (Sarotherodon melanotheron) is a paternal mouthbrooder. Pairs of adult black-chinned tilapia were raised in freshwater and the males were sampled during the mouthbrooding cycle. Sampling also occurred 10 days after release of the free-swimming fry for comparison. During the first week of incubation of the eggs, total androgens and estradiol were low (<5 and <0.3 ng/ml,...

Background: Heat shock may affect different aspects of oocyte maturation and its subsequent development to the blastocyst stage. A series of in vitro experiments was performed to determine whether physiologically heat shock (41°C) disrupts the progression of the ovine oocytes through meiosis, activation and blastocyst formation. Materials and Methods: The cumulus-oocyte complexes (COCs) were as...

The avian embryo has been a classical model to study early development because the embryo is easily accessible for manipulation of embryonic cells and structures. The usefulness of the chicken embryo increased with the development of quail-chick transplantation techniques (1,2). The ability to transplant Japanese quail cells into a chicken embryo provides a method to trace the developmental fat...

BACKGROUND This study was investigated the effects of culture media conditions on production of eggs fertilized in vitro of embryos from ovaries of high grade Korean native cow, Hanwoo. METHODS The IVMD 101 and IVF 100 were used for in vitro maturation of selected Hanwoo oocytes and In vitro embryo culture after in vitro fertilization, respectively. The IVMD 101 and IVD 101 were used for in v...