Physiological responses and non-specific immune parameters in Epinephelus moara exposed to repeated physical stress

Abstract

To evaluate effects of physical stress on physiological and non-specific immune parameters in Epinephelus moara, levels of cortisol, glucose, lactic acid in serum, as well as malondialdehyde (MDA), Alkaline phosphatase (AKP), acid phosphatase (ACP) and lysozyme (LZM) activities in liver were examined. Plasma cortisol levels increased significantly to peak levels at the first day in stressed individuals. Moreover, those levels were significantly higher with respect to control (P less than 0.05). Concentrations of glucose in serum has only a slight increase at the first day when subjected to stress (P greater 0.05). The levels of lactic acid, activity of ACP and AKP increased and significantly peaked during treatment; then, all of them dropped to the levels of control groups at the end of treatment. The concentration of LZM and MDA in liver had a significant increase and peaked during treatment; then it began to drop, and finally recovered to the level of control groups. The results indicate that E. moara presented significant physiological and immune responses when subjected to a repeated physical stressor. Also, cortisol and MDA changes could be used as bio-indicators for monitoring stress. The present study provides basic information for improved rearing and feeding protocols in this species.