Cellular and biochemical parameters in the crab Carcinus aestuarii after experimentally-induced stress: effects of bacterial injection, leg ablation and bacterial injection/leg ablation combination

The effects of bacterial injection, leg ablation and bacterial injection/leg ablation combination on cellular and biochemical parameters of the crab Carcinus aestuarii were evaluated. Total haemocyte count (THC), haemocyte volume, haemocyte proliferation, phenoloxidase (PO) activity in both haemocyte lysate (HL) and cell-free haemolymph (CFH) and CFH glucose levels were used as biomarkers of stress in crabs. After 24 h following bacterial injection, no significant variation in THC were observed, whereas haemocyte diameter and volume decreased significantly in injected crabs with respect to controls. Haemocyte proliferation and glucose levels increased significantly in injected crabs, whereas no significant variations in PO activity was recorded between control and injected crabs. THC increased significantly one-day after leg ablation, whereas it decreased significantly after 3 and 7 days. Haemocyte diameter and volume did not vary significantly between control and de-clawed crabs at each sampling times. In de-clawed crabs, haemocyte proliferation was significantly higher after 7 days, whereas glucose and PO activity increased significantly in CFH after 1 and 3 days. The bacterial injection/leg ablation combination caused a statistically significant decrease in both THC and haemocyte diameter and volume, whereas increased significantly glucose levels in CFH. Overall, results obtained demonstrated that stress conditions investigated in the present study affected both cellular and biochemical parameters in C. aestuarii. Results also indicated that crabs can cope with differing stressful conditions modulating their immune parameters depending on the kind of stress undergone. Although preliminary, our results may explain \u2013 partially at least \u2013 the great adaptability and widespread of C. aestuarii out of its native area