Study on respiratory metabolism changes of juvenile Penaeus monodon following strenuous activity

In order to provide scientific basis for the breeding and releasing of Penaeus monodon, we simulated the exhausted movement of the juveniles in the laboratory flume, then investigated their respiratory metabolic recovery after exhaustion exercise. With different recovery times after exhaustive exercise, there were significant changes in the total protein content (TP) and lactic acid (LA) concentrations as well as the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) in the hepatopancreas of the juveniles (P<0.05). There was significant difference in the LA concentration and LDH activity in abdominal muscles. The TP concentration in hepatopancreas was significantly higher than that of the control group after 4 h of exhaustive exercise, and returned to the control level at 48^th hour. The LA concentration of hepatopancreas was significantly higher than that of the control group at 12^th hour, and returned to the control level at 24^th hour. The activities of AST and ALT in hepatopancreas increased significantly during the 8^th to 12^th hour, and returned to the control level at 24^th hour. The activities of LDH and SDH increased and were significantly higher than that of the control group at  12th hour, and returned to the control level at 48th hour. The glycogen concentration (GLY) in the muscle decreased significantly after exhaustive exercise and returned to the control level at the 12^th hour. The LA concentration increased significantly after exhaustive exercise and decreased to the control level at 8^th hour. The LDH activity increased significantly after exhaustive exercise, and continued to increase during 1^st to 12^th hour, and remained significantly higher than that of the control group at 72^th hour. The anaerobic metabolism of the juveniles was significantly enhanced after exhaustive exercise, and exhaustive exercise could be performed again after 8 h; heaptopancreas was the place where the juveniles cleared metabolites, and began to deal with internal environment imbalance after exercise.