Abstract:
The study is divided into 3 experiments. The first was no the effect of calcium hypochloride on the variations of osmolality and minerals concentrations in four salinities (15, 20, 25, 30 ppt) were examined. The second was on the variable of osmolality and minerales concentrations and bicabonate in larviculture medium including the minerals change in Litopenaeus vannamei body at each larval stage (nauplius, zoea, mysis and postlarvae). The third was study on the effects of minerals supplementation in larviculture medium at four larval stages on growth, metamorphosis period and survival rate of L. vannamei larvae.The results of the study indicated that minerals concentration were generally affected by using calciumhypochloride in >=25 ppt for water treatment. Particularly, Na and Mg were significantly (p<0.05) decreased.Except for zoea stage, the osmolality in culture medium was significantly decreased (p<0.05). The significant (p<0.05) decrease of bicabonate in culture medium was found in nauplius, zoea and mysis stages. Concentrations of K, Na, Ca and Cl decreased significantly (p<0.05) in culture medium for nauplius stage. K and Mg were obviously detected in the body content of nauplius whereas Ca was missing. Concentrations of Ca and P decreased significantly (p<0.05) in culture medium at zoea stage while high content of Ca was found in the body. Minerals concentrations in culture medium at mysis and postlarval stages were not significantly changed (p>0.05). High content of Mg was found in the body content of mysis stage while high concentration of Ca and K were found in postlarval stage. Cu and S were not detected in all larval stages of L. vannamei.Bicarbonate was supplemented in larviculture medium at all larval stages except at the postlavae. Mg and K, Ca, Mg, Ca and K were respectively applied in culture medium for nauplius, zoea, mysis postlarval stages. Except for nauplius stage, survival rate of each larval stage of L. vannamei which minerals supplement was significantly (p<0.05) higher than that of the non-supplement one. Metamorphosis period and growth of each larval stage were not significantly different (p>0.05) between the two groups.