جستجوی مقالات مرتبط با کلیدواژه "acute toxicity" در نشریات گروه "شیلات"

A study was conducted to determine LC50 96h of Diazinon (an organophosphate insecticide) on juvenile Sterlet sturgeon (Acipenser ruthenus) at Shaheed Beheshti Sturgeon Hatchery (Rasht, Guilan, Iran). For this purpose, 180 juvenile Sterlet sturgeon (mean weight of 6.48±1.39 g) were used. Fish were randomly placed in 6 groups each with 3 replicates (five experimental treatments and a control group) in fiberglass tanks (75×50×15 cm). The experiments were carried out in static method according to Organization of Economic Cooperation and Development guidelines (O.E.C.D) for 96 hours. Physio-chemical parameters of water including temperature, oxygen, pH and total hardness were measured regularly throughout the study. Juvenile Sterlet specimens were subjected to concentrations of 3, 3.41, 3.87, 4.4 and 5 ppm and Probit analysis suggested the LC10, LC50, LC96 concentrations as 2.48, 3.56 and 5.17 ppm respectively. In hematological studies values of RBC, WBC and PCV were significantly varied in in experimental and control groups (P< 0.05). Exposure to Diazinon induced curvature of the spine, body trembling, rapid swimming and whirling, pale color, bruise on the head with eventual sinking to the bottom of the aquarium and death. Examination of gills showed edema and fusion in primary lamellae, swelling and fusion of secondary lamella, vacuole bearing, flattened and flaked secondary lamellae, separation of cells, necrosis and general hemorrhage with higher intensity at 4.4 and 5 mg/l concentrations. In liver tissues also edema, vacuole bearing cells, damage to cytoplasmic membrane, loss of granular appearance of the cytoplasm, pyknotic nuclei, karyolysis, karyorrhexis, necrosis and complete breakdown of the cell membrane at 4.4 and 5 mg per liter treatments were more likely than other treatments.

In this study, acute toxicity of Paraquat was studied on
Mesopotamichthys sharpeyi fingerling. The acute toxicity test was performed in static renewal system based in the standard method proposed by OECD during 96 h, physicochemical parameters of water including pH, dissolved oxygen and Temperature were monitored. In order to determine the lethal range of paraquat a range finding test was carried out. The acute toxicity test was preformed in 5 treatments in triplicates. The obtained data were analyzed by using Probit analysis with 0.05 confidence limit. According to the results of this study, 24 h LC50, 48 h LC50, 72 h LC50 and 96 h LC50 of paraquat on Mesopotamichthys sharpeyi was 6.84, 5.29, 2.57 and 1.49 mg/l respectively. The Maximum acceptable toxicant concentration (MATC) of paraquat on Mesopotamichthys sharpeyi was 0.14 mg/l and the lowest was observed effect concentration witch is equal to 96 h LC50 was 1.05 mg/l. in addition paraquat lethal toxicity takes place in a narrow range of toxicant concentration.

We treated 150 specimens of Acipenser nudiventris with diazinon and used 30 individuals as control to assess the haematological effects of the pesticide and LC50(96h) for the fish. The acute toxicity test lasting 96 hours was conducted on juvenile Acipenser nudiventris kept in aerated stagnant water contaminated with diazinon. The LC50(96h) values of diazinon for Acipenser nudiventris juveniles was 4.6 mg/l. The experimental groups of fish showed statistically significant difference in their erythrocyte, hemoglobin, leukocyte and differential leukocyte count (P<0.05). Acute toxicity effects of diazinon on the fish was recorded as lowered erythrocyte and lymphocyte count with a significant increase in developed neutrophil count (P<0.05). It is suggested that the change in erythrocyte and leukocyte count may have been caused as a result of disruption of hematopoiesis and a decrease in non-specific immunity level of the fish.