A microcalorimetric technique based on the metabolic heat-output was explored to evaluate the inhibition of cyanide on the mitochondrial metabolism of aquatic animal, Cyprinus carpio. The power-time curves could be divided into four parts： lag phase, active recovery phase, stationary phase, and decline phase, and the corresponding thermokinetic parameters were obtained. The maximum heat production rate Pmax decreased in a linear manner with the increase of concentration of cyanide, however, such mitochondria of aquatic animal were still metabolized actively even under the action of high concentration of cyanide. All the observations suggested that the mitochondria of this aquatic animal should exhibit considerable ability of cyanide-resistant respiration.
