Effects on acid-base balance, methemoglobinemia, and nitrogen excretion of European eel Anguilla anguilla after exposure to elevated ambient nitrite

Abstract

Haemoglobin, methaemoglobin, blood nitrite concentration and acid-ha,e balance were measured in European eel Anguilla anguilla following exposure to 0 (control). 0 142, 0.356. 0.751 and 1.549 mM nitrite in fresh water for 24h. Blood GOT (glutamate oxaloacetate transaminase) and GPT (glutamate pyruvate transaminase) activities and whole animal ammonia-N and urea-N excretions were also measured. Blood nitrite, methaemoglobin, PO2 (oxygen partial pressure), GOT, and whole animal ammonia-N excretion and urea-N excretion increased directly with increasing ambient nitrite concentrations, whereas blood pH, PCO2, and HCO3- were inversely related to ambient nitrite concentration. An accumulation of nitrite in the blood of A. anguilla following 24 h exposure to elevated ambient nitrite as low as 0.751 mM increased its blood methaemoglobin, PO2, GOT and nitrogen excretion, but decreased its PCO2 (carbon dioxide partial pressure), PCO2 and functional haemoglobin. (C) 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved.