| Ventilation volume (<img src="http:/img/fbpe/rbbio/v60n2/a08vg.gif" alt="a08vg.gif (265 bytes)" align="absmiddle"> mlH2O.min1 ), respiratory frequency (fR breaths.min1) and tidal volume (V T mlH2O.breath1 ) were measured in a group of Piaractus mesopotamicus (650.4 ± 204.7 g; n = 10) during normoxia and in response to graded hypoxia. The fR was maintained constant, around 100 breaths.min1, from normoxia until the O2 tension of the inspired water (PiO2) of 53 mmHg, below which it increased progressively, reaching maximum values (157.6 ± 6.3 breaths.min1) at 10 mmHg. The V T rose from 1.8 ± 0.1 to 6.0 ± 0.5 and 5.7 ± 0.4 mlH2O. breath1 in the PiO2 of 16 and 10 mmHg, respectively. The <img src="http:/img/fbpe/rbbio/v60n2/a08vg.gif"... |
