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Dietary selenium requirement for juvenile cobia, Rachycentron canadum L.
Author(s) -
Liu Kang,
Wang Xiaojie J.,
Ai Qinghui,
Mai Kangsen,
Zhang Wenbing
Publication year - 2010
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/j.1365-2109.2010.02562.x
Subject(s) - biology , zoology , selenium , juvenile , methionine , casein , biochemistry , ecology , chemistry , amino acid , organic chemistry
A 10‐week feeding trial was conducted to estimate the optimum dietary selenium (Se) requirement for juvenile cobia, Rachycentron canadum L. The basal diet was formulated to contain 50.6% crude protein from vitamin‐free casein, gelatin. A control diet (no added seleno‐ dl ‐methionine) and five experimental diets containing 0.20, 0.40, 0.60, 0.80 and 1.00 mg seleno‐ dl ‐methionine kg −1 were prepared. Each diet was randomly fed to triplicate groups of juvenile cobia with initial weight 6.27±0.03 g in a flow‐through system. The Se concentration in rearing water was monitored during the feeding period, and was not detectable. The dietary Se level significantly influenced the survival, specific growth rate (SGR), feed efficiency and the Se concentrations in the whole body and vertebra of cobia. The Se‐dependent glutathione peroxidase (EC 1.11.119) activity increased with an increase in the dietary Se levels ( P <0.05). Hepatic glutathione reductase (EC 1.6.4.2) activity was the highest in fish fed the diet with 0.21 mg Se kg −1 , and declined with an increase in the dietary Se levels. Based on broke‐line regression of SGR, the Se concentration in the whole body and vertebra, the Se requirements of juvenile cobia were 0.788, 0.811 and 0.793 mg Se kg −1 diet in the form of seleno‐ dl ‐methionine respectively.