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The impact of elevated water nitrate concentration on physiology, growth and feed intake of African catfish C larias gariepinus (Burchell 1822)
Author(s) -
Schram Edward,
Roques Jonathan A C,
Abbink Wout,
Yokohama Yanick,
Spanings Tom,
Vries Pepijn,
Bierman Stijn,
Vis Hans,
Flik Gert
Publication year - 2014
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12098
Subject(s) - catfish , clarias gariepinus , nitrate , biology , nitrite , zoology , aquaculture , plasma concentration , nefa , fishery , fatty acid , endocrinology , ecology , biochemistry , fish <actinopterygii>
Abstract The nitrate threshold concentration in rearing water of African catfish ( C larias gariepinus ) was assessed. Female African catfish with an initial mean ( SD ) weight of 154.3 (7.5) g were exposed to 0.4 (Control), 1.5, 4.2, 9.7 and 27.0 m M nitrate for 42 days. Mean ( SD ) plasma concentrations of nitrate increased from 71 (29) to 6623 (921) μ M at the highest ambient nitrate level. Mean ( SD ) plasma nitrite concentration ranged from 1.2 (0.5) to 7.9 (9.0) μ M . Haematocrit, plasma concentrations of non‐esterified fatty acids ( NEFA ), cortisol, glucose, lactate, osmolality, gill morphology and branchial Na + / K + ‐ ATP ase activity were not affected. Feed intake and specific growth rate were significantly reduced at the highest nitrate concentration. We advise not to exceed a water nitrate concentration of 10 m M (140 mg L −1 NO 3 ‐N) to prevent the risk of reduced growth and feed intake in African catfish aquaculture.