Dietary supplementation of fulvic acid for growth improvement and prevention of heavy metal accumulation in Nile tilapia fed with green mussel

The present study aims to evaluate the effect of dietary fulvic acid supplementation on the accumulation of Pb and Cd and the growth performance of Nile tilapia Oreochromis niloticus fed with diets containing green mussel with high Cd and Pb content. Nile tilapia juveniles with a mean body weight of 8.9 ± 0.6 g were randomly distributed into 15 aquarium units (100 L, 17 fish per aquarium). Five experimental diets were formulated to contain 10% mussel meal with high Pb and Cd concentrations, and five levels of fulvic acid, i.e. 0, 100, 200, 400 and 800 mg kg−1 and fed to the fish to the satiation level for 60 days of culture. The consumption of diets containing Pb and Cd resulted in the accumulation of these heavy metals in the fish, however, fulvic acid dietary supplementation could reduce the accumulation of the heavy metals. Furthermore, the dietary supplementation of fulvic acid up to 400 mg kg−1 had significantly improved the fish growth performance and feed utilization. In conclusion, the dietary supplementation of fulvic acid of 200 mg kg−1 could be recommended to prevent Pb and Cd accumulation and to enhance the growth of Nile tilapia fed with diet containing heavy metals.