The presence of
xenobiotic contaminants especially
metals in coastal
waters is a major concern as they are
immunotoxic to aquatic animals even at low concentrations. In our present study, mud crab Scylla serrata was exposed to three sublethal concentrations (0.4, 0.6 and 0.8 mg/L) of
nickel for 30 days under laboratory conditions and the alterations of
hematological parameters like haemocyte count,
clotting time, haemocyte viability, protein content and
immunomodulatory components like phenoloxidase,
phagocytosis and
superoxide anion generation were measured. In addition, the accumulation patterns of
nickel were measured in
gills,
hepatopancreas and
ovary. The accumulation was more in
gills when compared to
hepatopancreas and
ovary of crabs exposed to
nickel and was not detected in the control crabs. The results revealed a significant (P<0.05) induction of
superoxide anion generation and
phagocytosis activity in the haemolymph of
the crabs exposed to
nickel when compared to control. On the contrary, the rest of the parameters were significantly (P<0.05) reduced in the experimental groups when compared to the control. All the studied parameters exhibited a concentration dependent response.
