Effects of embryonic CO 2 exposure on the adult ventilatory response in quail: does gender matter?

Abstract

To test the hypothesis that the adult ventilatory response to CO 2 can be modified by exposure to CO 2 during development, we exposed Japanese quail ( Coturnix japonica) from two populations to 2% CO 2 throughout embryonic development. The ventilatory response to 6% CO 2 was subsequently measured in control and CO 2-exposed quail following a 6–9 week deacclimation period. In one population of quail, CO 2-exposed female, but not male, quail had a reduced ventilatory response to 6% CO 2 as adults ( P<0.001). Although control and CO 2-exposed quail had similar ventilation while breathing air, CO 2-exposed females exhibited a 26% reduction in mean ventilation at 6% CO 2, 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.