This study developed a computer-controlled closed-circuit respiratory calorimetry system to accurately measure oxygen (O₂) consumption and carbon dioxide (CO₂) production in broilers, which are essential for determining total heat production. The system includes components for controlling the chamber environment, quantifying O₂ use, filtering air, and absorbing CO₂. System accuracy was tested by burning 100, 150, and 200 g of ethanol (purity ≥ 99.7%) to compare actual O₂ consumption and CO₂ production with theoretical values. Repeatability for measuring dietary energy utilization was evaluated using three groups of six closed-circuit indirect respiratory calorimeters, each containing three 25-day-old male Arbor Acres broilers. Results showed that measured O₂ consumption and CO₂ production closely matched theoretical values (100.4 to 102.8%). Strong correlations were observed between metabolic body weight and both O₂ consumption and CO₂ production, as well as between these parameters and average daily feed intake. No significant differences were found among groups for energy values and utilization, with CV of inter-group for energy efficiency below 3.19%. These findings demonstrate that the system provides reliable, accurate, and repeatable measurement of energy utilization in broilers.

Read the full article in the Journal of Animal Science.