Effects of Lead and Cadmium Accumulation on Survival and Growth of the Nile Tilapia (Oreochromis niloticus) | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 10, Volume 26, Issue 6, November and December 2022, Page 155-171 PDF (626.82 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2022.271752 | ||||
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| Author | ||||
| Mostafa F. Abdelzaher et al. | ||||
| Abstract | ||||
| The current paper was designed to understand the quantitative uptake pattern of lead (Pb) and cadmium (Cd) using the Nile tilapia Oreochromis niloticus and their effects on their survival and growth performance, under laboratory conditions. A total of 300 fish individuals of Nile tilapia were randomly divided into five treated groups (control group; 2 groups exposed to low concentration “2% LC50” and 2 groups exposed to high concentration “10% LC50” of both Pb and Cd). Both control and treated groups were noticed for 60 days. The results of the current study revealed that the mortality rate was higher in fish exposed to Cd than in those exposed to Pb, while no mortality was recorded in the control group. All growth parameters (WG, DWG and RGR) of O. niloticus were retarded due to the exposure to either Pb or Cd at different concentration levels compared to the control group. However, the hepatosomatic index (HSI) values were always higher in fishes exposed to Pb at different concentration levels than the fish in the control group and these values were sharp in Cd exposures experimental groups during the first 30 days indicating hepatic hyperplasia or hypertrophy. Furthermore, the Pb and Cd accumulations in target organs were gradually increased with an increase in Pb and Cd concentrations and exposure time. After 60 days of exposure, the accumulation values of Pb in fish muscles were 2.64 and 8.67 µg/ g wet weight for T1 and T2, respectively; however, values of Cd in fish muscles were 2.23 and 3.87 µg/ g wet weight for T3 and T4, respectively. Results revealed that the bioconcentration factor (BCF) of Pb and Cd at low concentrations’ exposure was greater than that recorded at high concentrations’ exposure, especially on the days after the starting point until the saturation point (Saturated point recorded after day 45 in both Pb and Cd exposure). | ||||
| Keywords | ||||
| Nile tilapia; Oreochromis niloticus; Heavy metals; Survival rate; Bioconcentration; Bioaccumulation | ||||
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