Chloride inhibition of nitrite-induced methemoglobinemia in channel catfish (Ictalurus punctatus)

Journal of the Fisheries Research Board of Canada
None
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Abstract

Exposure of channel catfish (Ictalurus punctatus) fingerlings for 24?h to 1.0, 2.5, and 5.0?mg/L nitrite (pH?=?7; hardness?=?40?mg/L; temperature?=?22–25 °C) produced methemoglobin levels of 20.7?±?1.9%, 59.8?±?1.9%, and 77.4?±?1.4% (SE), respectively. However, methemoglobin levels were not elevated when fish were simultaneously exposed to 1.0, 2.5, and 5.0?mg/L nitrite and 25, 50, and 100?mg/L sodium chloride, respectively. Acclimation to sodium chloride for 24?h before exposure to nitrite did not enhance the inhibitory action of sodium chloride. Fish exposed to 5?mg/L nitrite for 5?h developed 42.5?±?3.8% methemoglobin. When transferred to water containing 5?mg/L nitrite and 250?mg/L sodium chloride, methemoglobin levels returned to normal within 24?h. Environmental chloride probably inhibits methemoglobin formation by competing with nitrite for entrance into the gills of the fish. An ionic ratio of 16 Cl- to 1 NO2- is capable of complete suppression of nitrite-induced methemoglobin formation. Bicarbonate ion present in the test water (1?meq/L) may also have contributed to the inhibitive action of chloride.
Publication type Article
Publication Subtype Journal Article
Title Chloride inhibition of nitrite-induced methemoglobinemia in channel catfish (Ictalurus punctatus)
Series title Journal of the Fisheries Research Board of Canada
DOI 10.1139/f79-160
Volume 36
Issue 9
Year Published 1979
Language English
Publisher NRC Research Press
Publisher location Ottawa, ON
Contributing office(s) Leetown Science Center
Description 4 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of the Fisheries Research Board of Canada
First page 1141
Last page 1144
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