Introduction: Heavy metals can have detrimental effects on farmed shrimps. These metals, such as lead, cadmium, and zinc, may enter shrimp farming ponds as contaminants. High concentrations of heavy metals in the water and environment can negatively impact the growth, health, and performance of shrimps. To prevent the adverse effects of heavy metals on farmed shrimps, it is crucial to control water input and output, regulate feeding regimes, and manage wastewater and waste properly. The present study investigated the accumulation and risk levels of three toxic metals, namely lead, cadmium, and zinc, in the muscles of Litopenaeus vannamei (western whiteleg shrimp) in the aquaculture farms of Gourdim region.
Materials & methods: Sampling was conducted in three ponds labeled as A (fed with concentrated feed only), B (concentrated feed + 1% probiotic), and C (concentrated feed + 2% probiotic), with three repetitions. After muscle separation in the laboratory, the metal concentrations were measured using atomic absorption spectroscopy.
Results: The findings of this research revealed the following sequence of heavy metal concentrations in shrimp muscle tissue: zinc> lead> cadmium. Additionally, only the concentration of lead was significantly lower in fiberglass ponds (0.067±0.012 mg/l) compared to soil ponds (0.07±0.013 mg/l). However, no significant difference was observed in the concentrations of zinc and cadmium between the two types of ponds. In soil ponds, the metal concentrations in shrimp muscle were as follows: zinc (14.18±0.08 mg/kg), lead (0.07±0.012 mg/kg), and cadmium (0.004±0.001 mg/kg). In fiberglass ponds, the metal concentrations were as follows: zinc (14.21±0.22 mg/kg), lead (0.067±0.012 mg/kg), and cadmium (0.003 ± 0.001 mg/kg).
Conclusion: Generally, the concentrations of all metals in control and probiotic-treated ponds were below the permissible limits. Therefore, it is recommended to implement appropriate control measures, including monitoring the shrimp's diet and controlling the inflow and outflow water of the ponds, to reduce the presence of harmful metals in this shrimp species. |
