Effects of an organophosphorus insecticide, trichlorfon, on hematological parameters of the giant freshwater prawn, Macrobrachium rosenbergii (de Man)

Hemolymph osmolality, ion concentration, acid–base balance, and immune parameters in Macrobrachium rosenbergii (15–20 g) were measured after 8 days of exposure to 0–0.3 mg l 1 trichlorfon. A significant depression in hemolymph osmolality and Cl 1 contents were observed with exposure to 0.3 mg l 1 trichlorfon. Similarly, hemolymph pH, HCO3 , and TCO2 decreased significantly when prawns were exposed to concentration of greater than 0.2, 0.1, and 0.1 mg l 1 trichlorfon, respectively. A notable increase in the hemolymph pCO2 was observed with 0.3 mg l 1 trichlorfon. However, no significant differences in hemolymph oxyhemocyanin or protein levels were observed among prawns with 0–0.3 mg l 1 trichlorfon. These findings may have resulted from histological changes in the respiratory epithelium and/or the inhibitory action of the nervous system of respiration. Phenoloxidase activity in the hemocytes of prawns decreased significantly with exposure to greater than 0.2 mg l 1 trichlorfon. This indicates that trichlorfon reduces the immune ability of M. rosenbergii. D 2004 Elsevier B.V. All rights reserved.