Abstract

This study aims to determine the effects of low temperature acclimation on the antioxidant defenses and ATPase activities in mud crab (Scylla paramamosain). The activities of ATPases and antioxidative enzymes, as well as malondialdehyde (MDA) content, were measured in the muscle of S. paramamosain acclimated at 5, 10, 15, and 27 °C (control group). The activities of superoxide dismutase, catalase, and glutathione peroxidase gradually declined with decreasing temperatures and then significantly lowered at 5 and 10 °C compared with those at 27 °C (P < 0.01 or P < 0.05). Significant accumulation of MDA, a lipid peroxidation indicator, was observed at 5 and 10 °C (P < 0.01). Compared with the control, the activities of four different ATPases significantly increased at 10 °C (P < 0.01 orP < 0.05). However, Na⁺/K⁺-ATPase and Mg²⁺-ATPase activities in the 5 °C group showed no significance compared with those in the control (P > 0.05). Ca²⁺-ATPase and Ca²⁺/Mg²⁺-ATPase activities at 5 °C were remarkably lower compared with those at 27 °C (P < 0.01). At low temperatures, antioxidant defense ability decreases with decreasing antioxidant enzyme activities, and MDA was accumulated in cell. The higher levels of ATPase activities at 10 °C, compared with the control, suggest compensation to maintain the physiological homeostasis of cytosol ion levels. However, ability to compensate for ATPase activity decreases beyond the critical value of low temperature (i.e., at 5 °C). Therefore, juvenile mud crabs should be cultivated in water at temperatures above 5 °C. This is an important guideline for farmers culturing mud crab in cold water. In addition, antioxidant parameters and ATPase activities can be used as biomarkers to assess the effects of low temperature acclimation on S. paramamosain.

Highlights