Energy metabolism and the fate of lactate during recovery from exercise in the Australian freshwater crayfish Cherax destructor

Abstract

Recovery following tail flipping by C. destructor involves regeneration of arginine phosphate and ATP in the tail muscle and the removal of lactate. High-energy phosphate reserves return to pre-exercise levels after 60 min, which corresponds with the time required for behavioural recovery. During recovery, the oxygen consumption rate increases and lactate accumulates in the tail muscle. The subsequent disappearance of lactate from this muscle and appearance of elevated levels of lactate in the external medium indicate that tail muscle lactate is excreted rather than metabolized. It is estimated that 40% of the 22.5 µmol ATP per gram of tail muscle required for regenerating arginine phosphate and ATP is obtained from anaerobic glycolysis. The remainder is provided by oxidative phosphorylation associated with elevated oxygen consumption during the initial 35 min of the recovery period.