Measurement of avian embryo respiration by an indirect calorimetric system

Accurate measurement of embryonic respiration can be used to determine the viabilityof the chicken embryo and the chick upon hatching. This measurement is based on both the rate of oxygen (O2)consumption and carbon dioxide (CO2) production. The respiratory. quotient (RQ), which is the ratio of the CO2 production to O2 consumption, indicates the energy source beingmetabolized. The metabolism of embryos under different environmentalconditions can be evaluated from heat production andRQ values. In this study, an embryo indirect calorimeter was evaluated for accuracy and reliability for use over an entireincubation period. The method of evaluation was a simulated control respiration source using the combustion of butanedrawn into the system at three different flow rates. The difference between the measured RQ values (mean0.64) and thetheoretical RQ value of butane value (0.62) was of interest (3%
than theoretical). Results from the butane combustionstudy indicated that the current calorimetry system designed for measurement of gas exchange rates in avian species can bereliably used to monitor O2 and CO2 exchange rates, system flow rates and RQ.