Jornal de Pesquisa e Desenvolvimento em Aquicultura

Abstrato

Effect of Different Levels of Dietary Calcium and Potassium on Growth Indices, Biochemical composition and Some Whole Body Minerals in Rainbow Trout (Oncorhynchus Mykiss) Fingerlings

Kalantarian SH *,Rafiee GH ,Farhangi M ,Mojazi Amiri B

Two completely randomized experimental designs were conducted to investigate the effect of different levels of dietary Ca (0.95%, 1.21%, 1.41% and 1.61%) and K (0.72%, 0.9%, 1.1% and 1.3%) on some growth indices, body biochemical composition and some whole body elements in rainbow trout fingerlings in a culture system. Tow basic diets with 0.95% Ca and 0.72% K were prepared and with CaCO3 for experiment І and K2CO3 for experiment ІІ, other dietary treatments were built. In initiation of each experiments, 25 pieces of rainbow trout fingerlings (12.18 ± 0.04 and 15.60 ± 0.05) introduced in each experimental units respectively, and were fed with dietary treatment ad libitum two times daily at 9:00 and 15:00 for a 8 week period. It was resulted that different levels of inorganic dietary-Ca in diets, had not significantly affected on growth factors (W1, WG, G%, SGR% day-1 and TGC), but different levels of inorganic dietary-K in diet had significantly affected (p<0.05) on these factors. FCR and survival rates did not show significant differences between the treatments in each experiment. In The first experiment, crude protein CP% and Ash% significantly increased and total lipid showed depletion with an increase in the dietary Ca (p<0.05). Change in inorganic dietary-Ca had significantly affected on Ca, P, Mn, Zn, Cu and Fe of whole body contents (p<0.05) and not affected the Mg and K of whole body. With increasing the inorganic dietary-K, diet with 0.9% total K, had significantly increased in CP% (p<0.05), however not significant differences between the trails in Ash% and total lipid% were observed. The Ca, K, P, Mg, Zn, Fe and Cu of whole body were significantly changed (p<0.05), and Mn had not significantly changed with increasing the inorganic dietary-K. Results were obtained in these studies, showed that, changes in amount of inorganic Ca in diets at the range of 0.95- 1.61% could not significantly affect on growth indices but dietary-K at the range of 0.72-1.3% affected the growth indices significantly (p<0.05). Significant effects on biochemical composition and some whole body minerals of cultured rainbow trout fingerlings with changes the dietary Ca and K were observed.