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The effects of temperature and hyperoxia on arterial P O 2 and acid‐base status in Piaractus mesopotamicus
Author(s) -
Soncini R.,
Glass M. L.
Publication year - 1997
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1997.tb01661.x
Subject(s) - piaractus mesopotamicus , biology , hyperoxia , acid–base homeostasis , arterial blood , zoology , perfusion , arterial ph , fish <actinopterygii> , base excess , medicine , biochemistry , fishery , lung
The effects of hyperoxia and change of temperature (range 20–30° C) on blood gases were studied in the teleost fish Piaractus mesopotamicus , native to several major river systems in Brazil. Large hyperoxia‐induced increases of arterial P o 2 ( P a o 2 ) indicated that true branchial blood shunts are negligible in relation to total gill perfusion. This implies that blood gases will be influenced by ventilation rather than by shunts. Acute variations of temperature ( t ) were accompanied by changes of arterial blood pH (on the average Δ p H a Δt −1 of — 0·015 units °C −1 ), due mainly to alterations of P a co 2 : 2·4 mmHg at 20° C, 5·0 mmHg at 30° C. Concomitantly, P a o 2 declined from 116 mmHg (20° C) to 89 mmHg (30° C). The data suggest that temperature‐induced changes of acid‐base status depend mainly on gill ventilation and that the decrease of P a o 2 with higher temperature is a result of this regulation.