Sub-lethal toxicity of indigo dye (Indigofera tinctoria) on Oreochromis niloticus juveniles

Abstract Background Textile dyes which are eliminated as unfixed through the effluent from textile industry cause deleterious effect on fresh water fish. Thus, toxicity tests were conducted using indigo dye Oreochromis niloticus juveniles (mean weight 30.00 ± 0.73 g) a test fish under bioassay system. Varying concentration of 0.00 (control), 0.5, 1.0, 1.5, 2.0, and 2.5 mg/l containing graded levels Indigofera applied in experimental tanks to determine lethal concentration. The LC 50 at 96 h was 1.3 water. histopathology (heart, gills, kidney spleen) quality parameters (Dissolved oxygen, pH temperature) determined standard methods behavioural responses observed. Results Histopathology heart, spleen revealed degeneration cells, space formation, slight cellular changes vacuolation among treatments especially higher 1.5 mg/l, 2.0 solution used except control. DO control significantly different units while there no significant variation temperature all units. Effects ( P < 0.05) throughout experiment. Behavioural exhibited by include irregular swimming, hyperventilation, rapid opercula movement, restlessness. exposure period both boosted these behaviours. Conclusions findings this study indicated that is toxic fish, movement mortality influenced dosage each duration exposure.