Haematological and Immunological Responses in Juvenile Sea Bass (Dicentrarchus labrax L.) after Short-Term Acute Stress.

The physiological effects of acute stress (induced by an intraperitoneal injection) on the haematocrit, haemoglobin, serum cortisol and glucose, haemagglutinins and lysozyme were investigated in juvenile sea bass Dicentrarchus labrax. A total of 40 fish were subjected to an intraperitoneal injection. Eight fish were sampled at 0, 2, 4, 24 and 48 h after acute stress and compared to unstressed fish (controls) sacrificed at the same times. Intraperitoneal injection resulted in significant changes in cortisol and glucose 4 and 2 hours after exposure to stress, respectively, but not in haematocrit and haemoglobin levels. No significant differences between stressed and control fish were recorded for lysozyme content and haemagglutinating activity throughout the experiment. In juvenile sea bass acute stress caused by intraperitoneal injection was mostly associated with the increase in common stress indicators (cortisol and glucose), while no clear response in terms of non-specific immune parameters was evidenced. Key Words: Dicentrarchus labrax, acute stress, intraperitoneal injection was mostly associated with the increase in common stress indicators (cortisol and glucose), while no clear response in terms of non-specific immune parameters was evidenced.