Acute effects of chromium on hemato-biochemical parameters and morphology of erythrocytes in striped catfish Pangasianodon hypophthalmus.

Chromium is considered the most detrimental pollutant to the aquatic organisms. The present experiment was conducted to determine the acute toxicity of chromium in view of its effects on hemato-biochemical parameters and the structure of erythrocytes in striped catfish, Pangasianodon hypophthalmus. Fish were exposed to seven different concentrations (0, 10, 20, 30, 40, 50 and 60 mg/L) of chromium, each with three replications for 96 h. After 96 h of exposure, the survived fish were sacrificed to measure hemato-biochemical parameters (hemoglobin, Hb; red blood cell, RBC; white blood cell, WBC; packed cell volume, PCV; mean corpuscular volume, MCV; the mean corpuscular hemoglobin, MCH and blood glucose). In addition, erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) of peripheral erythrocytes were assayed. No mortality was observed up to 10 mg/L, but 90% and 100% mortality was observed at 50 mg/L and 60 mg/L, respectively after a 96 h exposure period. The 96 h LC50 value through probit analysis was 32.47 mg/L. Hb (%), RBC (×106/mm3) and PCV (%) significantly decreased at 20, 30 and 40 mg/L of chromium, whereas WBC (×103/mm3), MCV (µm3) and MCH (pg) showed the opposite scenario. Blood glucose (mg/dL) levels significantly increased at 10, 20, 30 and 40 mg/L of chromium compared to 0 mg/L. Frequencies of ECA and ENA significantly increased with increasing chromium concentrations. This study indicates that chromium is highly toxic to striped catfish.

Acute toxicity of an organophosphate insecticide sumithion to striped catfish Pangasianodon hypophthalmus.

Sumithion is widely used for crop safety and eradication of tiger bugs (Cicindela spp.) from larval rearing aquaculture ponds. To satisfy the high demand of fries and fingerlings of widely cultured species striped catfish, spawns are produced in large scale in the hatcheries through hormone induced breeding, and subsequently these spawns are reared in nursery ponds and marketed to fingerlings vendors for stocking in grow-out ponds. Considering the importance of healthy fries and fingerlings the present experiment was conducted to evaluate the toxic effects of sumithion on striped catfish fingerlings. Fish were exposed for 96 h to six concentrations of sumithion (0, 3, 4, 5, 6 and 7 mg/l) each with three replications. The 96 h LC50 value was calculated using probit analysis. After 96 h of exposure fishes were sacrificed to measure hemato-biochemical (Hemoglobin, Hb; Red blood cell, RBC; White blood cell, WBC and blood glucose) parameters. In addition, formation of micronucleus (MN) was examined in the blood erythrocytes. The 96 h LC50 value of sumithion for striped catfish was 5.886 mg/l. The values of RBCs and Hb decreased significantly in different concentrations of the toxicant compared to control, while the values of WBC and blood glucose levels showed opposite scenario. Consequently, the frequencies of formation of MN increased significantly in different concentrations of the toxicant compared to the control. The results of the current study denoted that sumithion exerts toxicity to striped catfish. It is expected that the findings of the present research will help in the development of awareness of the concerned people about the toxic effect of sumithion as well as other insecticides and pesticides in the environment.