Premium
Carbon dioxide anaesthesia in rainbow trout: effects of hypercapnic level and stress on induction and recovery from anaesthetic treatment
Author(s) -
Bernier N. J.,
Randall D. J.
Publication year - 1998
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.1095-8649.1998.tb02022.x
Subject(s) - anesthesia , respiratory acidosis , general anaesthesia , carbon dioxide , anaerobic exercise , fight or flight response , hypercapnia , metabolic acidosis , acidosis , rainbow trout , medicine , biology , fish <actinopterygii> , physiology , biochemistry , ecology , fishery , gene
The physiological and anaesthetic effects of three different levels of air‐saturated and buffered CO 2 anaesthesia, P w co 2 =31, 78, or 125 mmHg, were examined in cannulated rainbow trout Oncorhynchus mykiss . Complete anaesthesia (no opercular movements) was not achieved by these hypercapnic levels after 20 min of CO 2 exposure. Although increasing P w co 2 reduced the induction times to the early stages of anaesthesia, it also resulted in increasing hyperventilatory, hypoxaemic, and acid‐base disturbances. After a 10‐min recovery period, while the respiratory acidosis component of the acid‐base disturbance was corrected, there was a significant metabolic acidosis. Recovery time was longest in the high P w co 2 treatment where 33% of the fish died. Two additional groups ( P w co 2 =37 and 78 mmHg) were exposed to an acute stress prior to the anaesthetic treatment. Stress reduced the hypoventilatory effects of the low P w co 2 treatment, increased the recruitment of anaerobic metabolism, and prolonged recovery time. Although the increase in plasma catecholamines elicited by the stress was small relative to the response obtained with the anaesthetic, stress prior to CO 2 anaesthesia impaired the efficiency of the treatment. Overall, our results suggest that P w co 2 levels above 37 mmHg and/or stress prior to the anaesthesia impair the efficiency of air‐saturated and buffered CO 2 anaesthesia by exacerbating the hypoxaemic effects of the hypercapnic treatment.