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Dziaman R., K∏yszejko B., Hajek G. 2005. The effect of MS-222 on the cardiac and respiratory function and behaviour of common carp, Cyprinus carpio L., during general anaesthesia. Acta Ichthyol. Piscat. 35 (2): 125-131.Background. Assessments of the efficacy of anaesthetics are usually based on observations of fish behaviour or changes in blood parameters. In this study we attempted to assess the process of anaesthesia, caused by MS-222, based on the measurement of heartbeat and respiratory frequency. Material and methods. The effect of four concentrations of MS-222 (75, 100, 125, and 150 mg · L -1 ) on heartbeat and respiratory frequency of common carp, Cyprinus carpio L., were studied using ECG. Concurrently (during general anaesthesia) fish behaviour was also observed.Results. The behavioural reactions were similar for all four treatments. The first symptom was agitation followed by sedation, loss of equilibrium, and deep anaesthesia. Small differences were observed during initial contact of fish with the anaesthetic. The ECG analysis, however, revealed significant differences in heartbeat and respiratory frequencies related to the concentration used. Irrespective of the MS-222 concentration used, the recovery time was similar in all treatments and did not exceed 5 minutes. Conclusion. The ECG method can be an important and objective tool supplementing the data acquired during visual observations of responses to anaesthesia. Its major advantage is the comparativeness of data.

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Background. Ventilation volume is a parameter used mainly for determining oxygen consumption of fish. The aim of the present work was to determine the ventilation volume of carp, under conditions of pure, aerated water. Material and methods. Stroke volume and breathing rate of carp representing three size groups (258.7 ± 40.1 g, 449.3 ± 39.6 g, and 663.2 ± 32.3 g) were studied within the temperature range of 10-25°C. Results. At 10°C the stroke volume of carp weighing 200-300 g was on average 2.25 ± 0.63 ml per 1 breath. This parameter in fish weighing 400-500 g was 2.70 ± 0.12 ml per 1 breath, while in fish attaining 600-700 g it amounted to 3.22 ± 0.41 ml per 1 breath. The breathing rate of all size groups ranged from 46.2 to 47.4 ± 8.51 cycles per min. A statistically significant increase of the stroke volume was recorded in all size groups at 15°C. At 20°C the increased stroke volume was accompanied by accelerated breathing rate. The temperature increase from 20 to 25°C did not cause any further increase of either breathing rate or stroke volume. Conclusion. The temperature-related regulation of the ventilation volume in carp is a two-step process. At 10-15°C the increased water volume pumped through the gills was achieved by an increased breathing depth (stroke volume). A further increase of the ventilation volume at 15-25°C resulted from acceleration of the breathing rate.

Propiscin has been one of the most popular aquaculture anaesthetics in Poland. It contains etomidate and is used to evoke general anaesthesia in fish (Kazuƒ and Siwicki 2001). The depressive effect of this agent on the heart action and ventilation in carp, Cyprinus carpio L., was described by Hajek and K∏yszejko (2004). The recorded bradycardia accompanying the anaesthesia was concluded to be a result of hypoxia. This study concentrates on examination of the direct effect of Propiscin on isolated and perfused carp heart.