To examine the possible influence of incubation substrate water potential on rigid-shelled chelonian eggs and hatchlings, rigid-shelled eggs from four clutches of Brisbane River turtle (Emydura signata) were incubated buried in vermiculite at water potentials of approximately -100, -350, and -850 kPa, and patterns of egg mass change and hatchling attributes were examined. All eggs hatched succe...

In decapod crustaceans, the conditions experienced during embryonic development trigger phenotypic plasticity of larvae at hatching. The objective this study was to test effects temperature Palaemon serratus on hatching larvae. We incubated egg-bearing females from eggs laying four temperatures (10, 15, 18 and 20°C). Weight, carbon nitrogen contents were measured newly laid freshly hatched dura...

Two experiments were conducted to evaluate effects of strain [five in Experiment (Exp.) 1 and six in Exp. 2)] and age (29, 47, and 57 wk in Exp. 1 and 29, 41, and 52 wk in Exp. 2) of commercial broiler breeders on incubation time and chick weight. Highly significant differences in egg weight were found among strains in both Exp. After adjusting for effects of egg weight, significant effects of ...

Incubation in most avian species involves transferring heat from parent to egg through a highly vascularized brood patch. Some birds, however, do not develop a brood patch. Unusual among birds, these species hold their eggs under the webs of their feet, but the role of the feet in heat transfer is uncertain. Often the webs are positioned between the feathered abdomen and the egg during incubati...

Many birds initiate incubation before clutch completion, which results in asynchronous hatching. The ensuing within-brood size disparity often places later-hatched nestlings at a developmental disadvantage, but the functional significance of the timing of the onset of incubation is poorly understood. Early incubation may serve to maintain the viability of early-laid eggs, which declines over ti...

objective: in recent years, antibiotics have been used widely in the glob to prevent and treat bacterial diseases. they injected into eggs to eliminate pathogens and prevention of egg transmission of disease, but the adverse effects of drugs have always been a major concern. there is little information available about the safety of tetracycline drugs in the embryonated eggs of the birds. the ob...

In eight Dutch or Belgian common tern (Sterna hirundo) colonies, breeding biology and food choice were determined, and 15 second eggs were collected from three-egg clutches for artificial incubation, biochemical analysis and analysis of yolk-sac polyhalogenated hydrocarbon (PHAH) levels. Results from these analyses were combined with biological data from the eggs remaining in each clutch. In so...