In this accidentally randomized design, the effect of various percentage of inorganic dietary calcium on ion profile of whole body content and water elements of rainbow trout culture system, were studied. A diet with %0.95 Ca was prepared and with adding CaCO₃, other diets with percents of (1.21%, 1.41% and 1.61%) Ca was made. In the first, 25 rainbow trout fish with 12.18± 0.04 initial meaning weight, was entered in each experimental units and fed with treatment diets ad libitum for 8 weeks and 2 times days in 9 am and 5 pm. Results showed that, changing the amount of Ca in diets, significantly affected on Ca, P, K, Mg, Zn, Cu and Fe in whole body content (p<0.05) but no significant difference observed in Mn of whole body content. Ca, Mg, K, Na and Cl in water changed, were different changed. The amount of Ca, Na and Cl in water, were significantly decreased (p<0.05) and K was significantly increased (p<0.05) compared with the first of experiment.
The results of this study indicated that, changing in amount of Ca in diets of rainbow trout, affected the ion profile of body and water elements of cultural systems and can influenced with positive or negative effects on absorption of these elements.