Effects of calcium supplement to purified diets on growth and bone mineralization in juvenile red sea bream and black sea bream

Juvenile red sea bream (av. body wt. 1.4g) and black sea bream (av. body wt .0.5g) were fed two purified casein based diets containing 0.34% (control) and 0.03% (unsupplemented) dietary calcium (Ca) for 10 weeks at 27.0 +/- 1. 4 degreesC. Final body weight, condition factor and hepatosomatic index wer e not affected by dietary Ca in both species. Feed efficiency in black sea bream was almost same. between two dietary groups, however, feed efficiency in red sea bream fed the Ca unsupplemented diet were slightly lower than t hat in fish fed the control diet. Dietary Ca levels did not affect blood ch aracteristics of red sea bream and black sea bream. In both species Ca and other mineral contents of the bone were independent of a dietary Ca supplem ent except that K and Mn contents of red sea bream fed the Ca unsupplemente d diet were significantly lower than those in the control. It appeared that Ca supplements to the purified diets are not necessary in juvenile red sea bream and black sea bream.