RESTING METABOLISM AND MYOFIBRILLAR MG2-ATPASE ACTIVITY OF CARP ACCLIMATED TO DIFFERENT TEMPERATURES()

Resting metabolism (RM) and myofibrillar Mg2+-ATPase activity at vario us temperatures were studied using carp reared at 10-degrees-C (group L) and 25.5-degrees-C (group H). The level of RM was higher in group L than group H at 19.5-degrees-C. On the basis of this result, it was c onsidered that a positive thermal compensation occurred in group L. My ofibrillar Mg2+-ATPase activities in the presence and absence of Ca2were greater in group L than group H at 5-degrees-C to 30-degrees-C. T he temperature dependences of RM and myofibrillar Mg2+-ATPase in the p resence of Ca2+ were greater in group L than group H in a measuring te mperature range below the rearing temperature, and a significant posit ive correlation was found in the relationship between these temperatur e dependences. This result suggested the RM and myofibrillar Mg2+-ATPa se activity in the presence of Ca2+ might be related. The levels of Ca -sensitivity tended to be lower in group L than group H at reaction te mperatures of 5 to 30-degrees-C, and were high at rearing temperature in groups L and H. The results suggested that Ca-regulation of myofibr illar ATPase was fully displayed at habitat temperature in carp acclim ated to different temperatures.