Synergistic effect of long-term feed deprivation and temperature on the cellular physiology of meagre (Argyrosomus regius).

The present study investigates the effects of water temperature under prolonged feed deprivation on meagre's (Argyrosomus regius) antioxidant defense system and apoptotic pathway. Therefore, triplicate groups of fish were subjected to 4 water temperatures (17, 20, 23, 26 °C) and deprived of feed for 60 days. Heat shock response (HSR) indicators (Hsp70 and Hsp90), activation of MAPK family members, uniquitination, antioxidant enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), and apoptotic indicators such as caspases levels and the ratio of Bax/Bcl-2 were determined in liver and muscle samples that were collected on days 0, 14, 41 and 60. Long term feed deprivation and temperature variations resulted in granulomatosis, HSR induction, MAPK activation, ubiquitination, and triggering of the antioxidant defense and apoptotic machinery of the meagre. Although these responses were differentially expressed at each different imposed temperatures, the most significant variations were mainly observed below 20 °C and above 23 °C. Correlation analysis showed a significant relation between the examined indicators. Thus, the obtained data herein indicated that long term food deprivation induces oxidative stress in fish.