The physiological response of oriental river prawn Macrobrachium nipponense to starvation-induced stress

Environmental stresses play critical roles in the physiology of crustaceans. Food deprivation is an important environmental factor and a regular occurrence in both natural aquatic habitats and artificial ponds. However, the underlying physiological response mechanisms to starvation-caused stress in crustaceans are yet to be established. In the present study, the hepatopancreas tissue of Macrobrachium nipponense was transcriptome analyzed and examined for starvation effects on oxidative stress, DNA damage, autophagy, and apoptosis across four fasting stages (0 (control group), 7, 14, and 21 days). These results indicated that a ROS-mediated regulatory mechanism is critical to the entire fasting process. At the initial stage of starvation (fasting 0 d ~ 7 d), ROS concentration increased gradually, activating antioxidant enzymes to protect the cellular machinery from the detrimental effects of oxidative stress triggered by starvation-induced stress. ROS content production (hydrogen peroxide and superoxide anion) then rose continuously with prolonged starvation (fasting 7 d ~ 14 d), reaching peak levels and resulting in autophagy in hepatopancreas cells. During the final stages of starvation (fasting 14 d ~ 21 d), excessive ROS induced DNA damage and cell apoptosis. Furthermore, autophagolysosomes and apoptosis body were further identified with transmission electron microscopy. These findings lay a foundation for further scrutiny of the molecular mechanisms combating starvation-generated stress in M. nipponense and provide fishermen with the theoretical guidance for adopting fasting strategies in M. nipponense aquaculture.