Abstract:
This study was conducted to evaluate the chronic exposure of cadmium on growth performance, bioaccumulation, and hematological parameters of genetically improved farmed tilapia (GIFT). Two concentrations of cadmium (50 μgL-1 and 100 μgL-1) with control were used. Twelve fish with an initial mean weight of 12.84 ± 0.53 g were randomly assigned quadruplicated treatments (total 144 fish) and the experiment lasted for six weeks. In the end, growth performance and feed utilization efficiencies were assessed by using % specific growth rate (%SGR), % average daily gain (%ADG) and feed conversion ratio. The pattern of Cd accumulation in different tissues and hematological parameters were examined. Mean body weight, %ADG, %SGR, hematocrit and packed cell volume were not affected by the treatments. A significantly higher survival rate (100 %) was observed in control followed by CD50 (87.50 %) and CD100 (78.13 %). The rate of Cd accumulation in various tissues was in the order of liver > gills > muscle > skin in each treatment. Among tested concentrations, the highest accumulation was observed in CD100 for each tissue. Both red blood and white blood cell count (2.21 ± 0.07 × 106 mm-3 and 468.00 ± 6.61 × 103 mm-3 respectively) were significantly higher in control and it was lowest in CD 100 (1.28 ± 0.04 × 106 mm-3 and 205.19 ± 8.94 × 103 mm-3). The results of this study supported the conclusion that there is a significant effect of the chronic exposure to cadmium on the bioaccumulation and hematological parameters of the GIFT tilapia even at the ecologically relevant concentration.
