To lower the lipid content in the basal diet, fish meal used in the experiment
was defatted first with ethanol (fish meal:ethanol=1:2 w/v,
6 h with intermittent shaking at 45 °C water bath, three times),
obtaining the lipid concentration of 1.8% dry matter. Seven low-fish
meal experimental diets with similar proximate compositions (42%
crude protein and 11% lipid) were formulated, differing only in the
lipid source