A face mask for estimation of whole body leucine turnover in unanesthetized beagle dogs

As part of a long-term study of protein and energy metabolism in Beagle dogs, a latex face mask was developed to facilitate respiratory gas collection. The mask described here is easily assembled using readily available materials and meets the following criteria: small dead air space, lightweight, readily acceptable by conscious dogs over a prolonged period of time, leakproof , and inexpensive. The mask has been successfully used with L-[1-13C] leucine to measure 13CO2 excretion rates in studies of leucine metabolism.