The objective of present study was to determine the effect of different concentrations of industrial effluents on water quality, growth performance and histology of major carps. LC50 for each species Catla catla, Labeo rohita and Cirrhinus mrigala were determined separately as 275.42 ml/L, 245.47 ml/L and 186.21 ml/L, respectively. Three sub-lethal concentrations of textile industries effluents were made as E-1 (1.5 %), E-2 (3 %) and E-3 (4.5 %) given to polyculture experimental groups in triplicates for three months.
Histopathological changes in the gill, kidney and liver of three species were observed. Histopathology of various organs showed maximum damage in the fishes of E-3 containing aquariums while E-1 and E-2 showed mild changes in the histology of organs. Gills were found to more damaged among all organs and muscles were least.
Maximum damages showed in gills included hypertrophy and hyperplasia, shortened, curled secondary lamellae along with enhanced number of mucous cells, clustered fibers within primary lamella, distorted basal cells and vacuolization. Maximum histopathological alteration showed in liver of studied fish species were dilated and congested central vein, damaged sinusoids, ruptured hepatocytes with eccentric nuclei, hypertrophy, dysplasia of hepatocytes (disorderly growth) and vacuolization. kidney showed severe necrosis, degeneration of glomerulus, hyperplasia and vacuolization. Muscles showed disorganization of nuclei, changes in myofiber, vacuolization and curling and clubbing of fibers. It has been concluded that Cirrhinus mrigala was more sensitive with respect to growth parameters and histopathological alterations in its various organs as compared to other two species. Conclusively, histopathology performed the reliable role for the evaluation of environmental pollution.