Effect of turning upon the sub‐embryonic fluid and albumen of the egg of the Japanese quail

Detection of early embryonic development in chicken eggs using visible light transmission

“…After the start of SEF formation, mechanical properties of the albumen like density and viscosity change owing to the loss of water and ions (Meuers and Egbers, 1990;Babiker and Baggott, 1992). By measuring viscosity with a compression test on cooked albumen samples, difference in viscosity between the albumen at the yolk-side and at the shell-side was demonstrated.…”

Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)

“…In the blastoderm samples only gene expression for CA IV was affected by egg turning, with maxima at 84 and 96 h of incubation (0Á20 and 0Á24 of the incubation period), times located approximately in the middle of the critical period. This is also the time of peak SEF mass in the Japanese quail (Babiker and Baggott, 1992). If, as seems probable, enhanced CA IV gene expression results in increased enzyme activity and endodermal cell ion transport, these changes could account for the additional fluid mass observed in turned eggs at 84 and 96 h of incubation (Babiker and Baggott, 1992).…”

“…This is also the time of peak SEF mass in the Japanese quail (Babiker and Baggott, 1992). If, as seems probable, enhanced CA IV gene expression results in increased enzyme activity and endodermal cell ion transport, these changes could account for the additional fluid mass observed in turned eggs at 84 and 96 h of incubation (Babiker and Baggott, 1992). In unturned eggs gene expression for CA IV at these times did not differ from earlier sampling times: presumably permitting continued SEF formation yet without forming the additional fluid mass produced with egg turning (Deeming, 1989c;Babiker and Baggott, 1992).…”

“…In order that embryonic tissue can access this water, it is transferred from the albumen to the yolk sac in the early part of incubation, a process resulting in the production of sub-embryonic fluid (SEF) by the blastoderm . In the Japanese quail the bulk production of SEF started at 48 h of incubation, with a peak in mass from 84 h (Babiker and Baggott, 1992). In both the domestic fowl and Japanese quail, static incubation reduced the mass of SEF during the period of its formation (Deeming, 1989c;Babiker and Baggott, 1992;Baggott et al, 2002).…”

“…Alternatively, or in addition, it was suggested that the lower rate of expansion of the area vasculosa present in unturned eggs (Deeming, 1989a) might also reduce SEF mass. However, neither hypothesis provides a complete explanation of the occurrence in turned eggs of additional fluid at the time of maximum SEF mass (Babiker and Baggott, 1992). An increase in ion transport specifically at this time would be a potential mechanism.…”