Accumulation of Nitrite in the Tissues of Penaeus monodon Exposed to Elevated Ambient Nitrite After Different Time Periods

Abstract

Penaeus monodon (29.42 ± 0.39 g) that had been exposed individually to 0.001 (control), 0.07, 0.36, 0.72, and 1.44 mM nitrite in 25 ppt sea water were examined for the nitrite accumulation in hemolymph, gill, eyestalk, heart, foregut, midgut, hepatopancreas, and muscle and nitrite uptake after 1, 3, 6, 12, 24, and 48 h, respectively. Concentration of nitrite in the tissues increased directly with ambient nitrite and exposure time except for muscle. P. monodon following 48-h exposure to 0.36 mM nitrite, nitrite concentration progressively increased from the muscle (0.40 μmol/g), hepatopancreas (1.24 μmol/g), gill (1.82 μmol/g), foregut (2.03 μmol/g), hemolymph (0.39 μmol/mL), heart (2.43 μmol/g), eyestalk (3.07 μmol/g), and to the midgut (4.14 μmol/g), which is 1.1, 3.4, 5.0, 5.6, 6.6, 6.8, 8.5, and 11.4 times the ambient nitrite concentration, respectively. It is concluded that when P. monodon is exposed to ambient nitrite, nitrite is immediately incorporated in the hemolymph and midgut via branchial chloride uptake of NO₂ ⁻, and accumulated in the tissues.