Nitrogenous excretion and arginase specific activity of kuruma shrimp Marsupenaeus japonicus exposed to elevated ambient nitrite

Abstract

Nitrogenous excretion and arginase specific activity were measured while Marsupenaeus japnoicus Bate (7.4 +/- 1.2 g) were exposed to 0 (control), 0.36 and 1.39 mM nitrite at 30parts per thousand (g kg(-1)) salinity for 24 h. Excretions of total-N, organic-N, urea-N, and ammonia-N increased significantly with an increase of ambient nitrite. Arginase specific activities of hepatopancreas and hemolymph increased directly with ambient nitrite. The fact that M. japonicus following exposure to 1.39 mM nitrite increased its arginase specific activity indicated an argininolysis in reducing joint toxicities of metabolic ammonia and incorporated nitrite. (C) 2004 Elsevier B.V. All rights reserved.