Histopathological studies and oxidative stress of synthesized silver nanoparticles in Mozambique tilapia (Oreochromis mossambicus)

To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia （Oreochromis mossambicus） were maintained in 10 L glass aquaria,and exposed to a graded series of synthesized silver nanoparticles （Ag-NPs） at 25,50 and 75 mg/L for eight days.The LC 50 value was 12.6 mg/L.Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs,which resulted in heavy accumulation of free radicals.Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure.The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.

Study of mosquito control using larvivorous fish Danio rerio Hamilton and Oreochromis mossambicus Peters

Objective:To evaluate the larval consumption rate of Danio rerio(D.rerio)and Oreochromis mossambicus(O.mossambicus)for the control of filarial vector mosquito Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fishes D.rerio and O.mossambicus were tested by feeding assay against Cx.quinquefasciatus for 24 h.Results:After 24 h of feeding assay the fishes D.rerio and O.mossambicus exhibited potential reduction rate of Cx.quinquefasciatus larvae.Conclusions:The present research work demonstrates that the D.rerio and O.mossambicus can be used for integrated mosquito management,which is simple and safe to non target organisms.