Male Green Mud Crab (Scylla paramamosain) Is More Vulnerable to Handling Stress than Female: A Comprehensive Insight into Physiological Changes and Health Status.

The current research investigated the effects of repeated mild handling stress (RMH) and acute handling stress (AHS) in male and female green mud crabs (Scylla paramamosain) on production, hemolymph biochemistry, immune system, antioxidant defense, endoplasmic reticulum stress gene expression, stress response, energy, and ion homeostasis. Gill, hepatopancreas, hemolymph, and muscle of 4 groups (F, M, F-RMH, and M-RMH) were sampled after 60 days of farming and after 27 h of AHS. No significant difference in growth performance and survival rate after 60 days was identified among the groups. Habituation in the M-RMH groups was observed (as shown by behavior change) and resulted in reduced fighting and broken legs. The lowest survival rate (9.09%) after AHS was observed in M crabs, which coincided with lower values of total protein in the gill, lysozyme, peroxidase, total antioxidant capacity, and glucose in the hemolymph, and higher levels of total amino acid, lactate dehydrogenase, sodium, and cholesterol in the hemolymph. Habituation may mitigate stress and aggression, which are significant issues in crab aquaculture.