Effect of prolonged captivity on the hemolymph profile of tachypleus gigas

Horseshoe crabs amebocyte cells degranulate to form a gel clot when in contact with endotoxins. This phenomenon is the basis of both Horseshoe crab immune system and detection of endotoxin in biologicals. The present study investigates the amebocyte cells quality in Tachypleus gigas pre and post bleeding under captivity. Wild and captive horseshoe crabs (5 months captivity) were bled in 6 anticoagulant formulations (A, B, C, D, E and F). No profound difference in cell density between captive and wild groups with the mean value of 0.883×10 a cells/mL and 0.917×10 cells/mL, respectively. while, the cell viability of the captive group was significantly lower than the wild crabs (F=808.075, p<0.001). Anticoagulant formulation significantly affected cell viability and cell morphology in both captive and wild groups (p<0.001). Amebocyte cells collected from the wild T. gigas using optimum anticoagulant (formula C) showed 0.6 ×10 cells/mL cell density and 86.9% cell viability, while morphology analysis revealed the percentage of contracted, granular flattened and degranulated flattened cells were 14.62%, 71.39% and 14%, respectively. The anticoagulant formulations showed varying capabilities in maintaining cell viability due to its buffering and chelating capacity. We conclude that captivity has a negative effect on the amebocyte cell quality.