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Salinity is the most variable ecological parameter in the lagoon with daily and seasonal variations . The changes in growth, serum biochemistry and antioxidant enzymes activities of Cardisoma armatum were examined during 84-day exposure to five different sublethal salinities (0, 5, 10, 15 and 20 ppt). At the start of the trial, the crab initial average body weight was not significantly different (P > 0.05). The highest weight gain was recorded in 15 ppt (47.40±1.01 g), followed by 20 ppt, 10 ppt and 5 ppt with no significant differences between them. At the end of 84 days experiment, the crab exhibited the lowest body weight growth (48.29 %) at 0 ppt and the highest (81.04±1.08%) at 10 ppt. The 10 ppt treatment had the highest specific growth rates (0.31±0.11 %/day), followed by 5 ppt, 20 ppt, 15 ppt, and then 0 ppt treatments. Aspartate and alanine aminotransferases significantly decreased after 0 ppt, but mean serum protein value increased with salinity increase. Greater activities of catalase, superoxide dismutase and malondialdehyde were recorded in 5-20 ppt. All the antioxidant enzyme activities (with the exception of glutathione) showed significant differences. Thus, deviation from the brackish water condition adversely affects the growth and immune functions of the gecarcinid, resulting in population decline in reclaimed wetlands. [ABSTRACT FROM AUTHOR]

Low insecticide exposure has been shown to cause profound effects on non-target organisms, including crabs. Therefore, the changes in hematological parameters, serum biochemistry and antioxidant enzymes in the Gercacinid Crab, Cardiosoma armatum were assessed during 28-day exposure to four concentrations of organophosphate chlorpyrifos (0.003, 0.006, 0.03 and 0.06 mg/l). The results showed a significant (P= 0.0) decrease in packed cell volume and total haemocyte count of the exposure crabs (except in 0.003 mg/l concentration) compared to control group. There were no significant changes in hemocyte sedimentation rate, granulocyte and agranulocyte, although all exposure groups increased in hemocyte sedimentation rate and agranulocyte with respective ranges of 3.00-3.02 mm/hr and 64.00-67.00 %. Except for alkaline phosphatase, there were no significant variation in the biochemical profile of both the control crabs and exposure crabs, although organophosphate chlorpyrifos exposure induced increase in all the measured biochemical parameters. The serum protein level and the activities of the enzymes (superoxide dismutase, catalase and malondialdehyde) were inhibited in exposure groups. The changes in these hematoimmunological parameters of the crabs were suitable biomarkers of a sub-lethal exposure to chlorpyrifos at the concentrations tested, and this will be useful in biomonitoring of aquatic environment. [ABSTRACT FROM AUTHOR]