Effects of embryonic CO2 exposure on the adult ventilatory response in quail: does gender matter?

Abstract

To test the hypothesis that the adult ventilatory response to CO2 can be modified by exposure to CO2 during development, we exposed Japanese quail (Coturnix japonica) from two populations to 2% CO2 throughout embryonic development. The ventilatory response to 6% CO2 was subsequently measured in control and CO2-exposed quail following a 6-9 week deacclimation period. In one population of quail, CO2-exposed female, but not male, quail had a reduced ventilatory response to 6% CO2 as adults (P<0.001). Although control and CO2-exposed quail had similar ventilation while breathing air, CO2-exposed females exhibited a 26% reduction in mean ventilation at 6% CO2, primarily due to a reduced tidal volume. In contrast, the identical incubation treatment had no effect on the ventilation of either gender in a second population of quail. It appears that developmental plasticity in the hypercapnic ventilatory response may generally be greater in females, although this conclusion may vary depending on genetic factors.