Protective effect of zinc on related parameters to bone metabolism in common carp fish (Cyprinus carpio L.) intoxified with cadmium

The short term effects of waterborne cadmium (Cd+2) on the levels of serum parameters related to bone metabolism including calcium (Ca), inorganic phosphorus (P-i) and alkaline phosphatase (ALP) in common carp fish (Cyprinus carpio L.) were studied. Fish were treated with varying concentrations of Cd+2 (0.22, 1.1 and 2.2 mg l(-1)) daily for 14 days. The results obtained show that serum P-i and ALP concentrations were elevated by increasing Cd+2 concentration in water containing fish whereas serum Ca level was decreased. At the same time, the protective role of waterborne zinc (Zn+2, 1 mg l(-1)) on the same parameters was also investigated. Results showing that daily treatment of fish with Zn+2, increased the concentrations of Ca and ALP in serum by 2.07 and 1.86 fold and decreased serum P-i level by 57.7% in comparison with Cd+2 treatment. The combination of Cd+2 and Zn+2 on the same parameters was studied next. There was a significant (P < 0.05) elevation in serum Ca and ALP levels in comparison with Cd+2 treatment. Decreasing in serum P-i level was not significant in comparison with Cd+2 treatments. The protective effect of Zn+2 on Cd+2 disturbances in serum parameters related to bone metabolism in this manuscript has been also discussed.