ABSTRACT
Pesticides can induce changes in behavior and reduce the survival chance of aquatic organisms. In this study, the toxic effects of glyphosate suspension (Glyphosate Aria 41% SL, Tehran Iran) on behavior and tissues of common carp (Cyprinus carpio) were assessed. For this purpose, a 96 h LC50 of glyphosate suspension (68.788 mL·L-1) was used in the toxicity test. All individuals were divided into control and treatment groups with four replicates. Exposure operations were performed under two conditions: increasing concentration of suspension from 0 to 68.788 mL·L-1; then, decreasing to the first level. The swimming pattern was recorded by digital cameras during the test and tissue samples were collected at the end of the test. There were significant differences between the swimming pattern of treated individuals and control ones during both steps. The sublethal concentration of glyphosate led to hypertrophy, hyperplasia and hyperemia in the gill of fish. However, changes were obvious only after sampling. The exposed fish also displayed clinical signs such as darkening of the skin and increasing movement of the operculum. Moreover, glyphosate suspension affected swimming patterns of fish suggest that the swimming behavior test can indicate the potential toxicity of environmental pollutants and be used as a noninvasive, useful method for managing environmental changes and assessing fish health conditions by video monitoring.
ABSTRACT
This study investigates acute toxicity and histological effects of Lindane insecticide on intestinal tissues of immature grass carp (Ctenopharyngodon idella). For these purposes, 105 fish were exposed to different concentrations of Lindane for 96 h in 5 groups with 3 replications. Samples of intestinal tissues were prepared in both control and exposure groups during and after the toxicity test. Vaculation, necrosis, bleeding and epithelial degeneration were apparent in the intestine tissue of treated individuals. The LC50 96 h of Lindane was 0.788 ppm in the present study, also the results showed besides pesticide-induced lesions, symptoms of abnormal swimming, anxiety, tendency to swim near the surface, and death due to terminal toxicity with mouth widely open. The exposed fish were pale in color, showed oxygen deficit and severe respiratory problems. Overall, our results confirm the toxicity of different concentrations of Lindane insecticide affecting behavior, intestinal function and inducing tissue lesions of immature grass carp.
