Role of fulvic acid on the reduction of cadmium toxicity on tilapia (Oreochromis niloticus)

摘要

The effect of fulvic acid on cadmium (Cd) toxicity, the impact on fish immunological, and haematological changes in Nile tilapia (Oreochromius niloticus) were studied. The fish (100±10g) were exposed to 10 ppm Cd alone or with 0.1, 0.2 and 0.3 ppm for 15 and 45 days. Cd exposure reduced significantly (P<0.04), for example the erythrocyte count (RBCs), haemoglobin content (Hb), haematocrit value (Hct), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration. These parameters were improved when fulvic acid was applied with Cd. The values of RBCs, Hb, Hct, MCH and MCHC were increased significantly in the control fish group. The addition of fulvic acid to Cd contaminated medium considerably reduced metal absorption and accumulation in fish tissues, while metals in water and faeces increased. Fish exposed to Cd alone accumulated 2.15 and 5.970 mg Cd/g dry weight in the liver tissue over 15 and 45 days, respectively. Cd reduced significantly to 1.292 and 4.16.; 0.92 and 3.791; and 0.41 and 2.43 mg Cd/g dry weight tissue in fish exposed to 0.1, 0.2 and 0.3g fulvic acid/L over 15 and 45 days, respectively. Similar trends were observed in gills and musculature.