The influence of gas composition in the air cell on pipping and liver metabolism in embryonic chicks.

In chick embryos, time of pipping is accelerated after repeated gassing the air cell with N2, CO2, or by sealing the egg shell in the area of the air cell with glue. Gassing the air cell with 95% O:2-5% CO2, or pure O2, was followed by a retardation of pipping. Furthermore, gassing with N2, or sealing the air cell with glue, exerted an accelerating effect on the decrease of hepatic glycogen and ATP. Following gassing with 95% O2-5% CO2, the reverse effect on glycogen and ATP was observed. It is suggested that the increase of the CO2/O2 ratio, occurring in the air cell at the end of incubation, acts as a stimulus for both pipping and metabolic changes in the liver.