Gaseous metabolism of the chicken embryo and hatchling during post-hypoxic recovery

In neonatal mammals, the drop in oxygen consumption (V˙O2) during moderate degrees of hypoxia is a manifestation of metabolic depression, and occurs without anaerobic energy compensation. We examined the possibility that embryos also respond to hypoxia with a similar hypometabolic response, by measuring the extent of the O2 debt during post-hypoxic recovery. In chicken embryos at incubation days 11 (E11) and 16 (E16), and hatchlings on the day of hatching (H1), V˙O2 and carbon dioxide production (V˙CO2) were measured with an open flow system. The protocol consisted of 1