Der einfluß von temperaturänderungen anf enzyme der fischmuskulatur. Versuche mit Rhodeus amarus

The enzyme activities estimated in the muscles of Rhodeus amarus (Bloch) may vary according to the kind of muscle, age and sex of the test individuals, as well as with the time of day, and the season. Oxygen consumption of individuals acclimated to different temperatures was tested at 22°C. At low adaptation temperatures no adaptation was found; at high adaptation temperatures, however, compensation could be ascertained. In view of the considerable fluctuation of the enzyme activities, estimated from individuals adapted to different temperatures, a relation to certain adaptation types, established by Precht (1961b, 1968), is hardly possible. During the first days following sudden or slow changes of adaptation temperature (increase or decrease) more or less marked fluctuations of enzyme activities were obtained. Later, however, in accordance with the proceeding adaptation, a new, labile balance was established. Temperature changes represent a physiological stress even within normal temperature ranges. This fact requires general attention in studies on biological processes. Disturbance of a newly established balance of enzyme activities can be obtained, when test fishes are exposed to high temperatures. This finding may be of importance in regard to the heat resistance of the animals.