Blood gases and acid-base status in chiken embryos with naturally varying egg shell conductance

Abstract

In chicken eggs selected for widely values of specific water vapor conductance, g H 2O (= water vapor conductance per freshly laid egg mass), P CO 2 , pH, P O 2 and hematocrit were measured in arterialized blood sampled from an allantoic vein (after 16 days of incubation) or in blood termed ‘venous’, sampled froman allantoic vein (after 18 days of incubation). Both arterialized and ‘venous’ P CO 2 were inversely related to g H 2O . Since the variations of blood plasma pH with P CO 2 were smaller than predicted for true plasma, partial compensation by appropriate non-respiratory changes of plasma bicarbonate concentration must have occured. Only with extremely high and low g H 2O a definite alkalosis and acidosis, respectively, were observed. Both arterialized and ‘venous’ P O 2 tended to diminish with decreasing g H 2O . The hematocrit value showed a tendency to increase with decreasing g H 2O and with decreasing arterialized P O 2 .