Oxidative Stress and Toxico-Pathic Branchial Lesions in Cyprinus carpio Exposed to Malachite Green

Impact of untreated and microbially treated equalization tank effluent of textile industry on freshwater fish Channa punctata using haematological, biochemical, histopathological and ultrastructural analysis

The unregulated expulsion of untreated or partially treated industrial effluents poses serious threat to the aquatic ecosystem. Therefore, in the present study fish Channa punctata were exposed to untreated and microbially treated equalization tank effluent of textile industry and toxicity studies were carried out for 45 days. The study was planned to analyze the toxicity proffered by textile effluents through haematological, biochemical, histopathological and ultrastructural analysis in blood, liver and gill tissues of fish. While comparing untreated and microbially treated effluent exposed groups haematological parameters were significantly (P ≤ 0.05) less in the untreated effluent exposed group whereas White blood cell count was highly escalated. However, in the microbially treated groups, the alterations were less severe. Increased malondialdehyde content indicating oxidative stress, reduced Catalase (CAT) and Superoxide dismutase (SOD) activity showing a weakened antioxidant defence system and increased glutathione activity was also perceived in untreated effluent exposed groups in comparison to microbially treated groups. Histopathological alterations in gill (telangiectasia, lamellae fusion, breakage, vacuolization and bending of lamellae) and liver (sinusoid dilations, fusion, necrosis and congestion) were more pronounced and severe in the untreated effluent exposed group as compared to microbially treated group. The results observed in histopathology were further reaffirmed by scanning electron microscopy. The study clearly highlights less alterations and deformities in microbially treated effluent groups in comparison to untreated effluent groups. These findings, therefore, necessitate the search for more effective microbial inocula for the better treatment of effluents in order to protect the aquatic life as well as human beings.

Highlights

Channa punctata exposed for 15, 30 and 45 days to untreated and microbially treated equalization tank effluent of textile industry.Untreated and microbially treated effluent exposed fish elicited alterations in blood, liver and gill tissuesHaematology, biochemical, histopathology and ultrastructural analysis resulted in massive pathologies in groups subjected to untreated effluent inducing maximum damage after 45 days of exposure.Less pronounced toxicity in fish C. punctata was observed in fish exposed to microbially treated effluent indicating its efficacy in toxicity reduction.

Assessment of textile industry effluent (untreated and microbially treated) induced genotoxic, haematological, biochemical, histopathological and ultrastructural alterations in fresh water fish Channa punctata

The unregulated expulsion of untreated textile water into water bodies is a major hazard to aquatic ecosystems. The present investigation was contrived to estimate the impact of textile dye bath effluent (untreated and microbially treated) on fish Channa punctata. Untreated effluent-exposed fish showed extremely altered behaviour (air gulping, erratic and speedy movements, increased opercular activity) and morphology (deposition of dyes on skin and scales, high pigmentation, mucus exudation). Significantly increased micronuclei (1.61-, 1.28-, 1.38-fold) and aberrant cell frequency (1.37-, 1.45-, 1.28-fold) was observed in untreated group as compared to treated group after 15, 30, and 45 days of exposure. Tail length, % tail intensity, tail moment and olive tail moment were also enhanced in all the exposed tissues. However, maximum damage was noticed in gill tissues showing 1.19-, 1.37-, 1.34- and 1.50-fold increased TL, %TI, TM and OTM in untreated group as compared to treated group after 45 days of exposure. On comparing untreated and treated groups, increased blood parameters and significantly reduced white blood cell count (WBC) were noticed in treated group. Significantly enhanced alterations in biochemical parameters were also analysed in untreated group. Reduced alterations in enzymological levels of fishes exposed to treated effluent indicate lesser toxic nature of the degraded metabolites of dye. Histological analysis in fishes exposed to untreated effluent showed several deformities in liver (necrosis, congestion, fusion of cells and melanomacrophage infiltration) and gill tissues (necrosis, bending of lamellae and severe aneurysm). Scanning electron microscopy (SEM) analysis further reaffirmed the pathologies observed in histological analysis. Fewer structural alterations were noticed in treated effluent fishes. The results concluded that untreated effluent inflicted toxicity potential on morphology as well as physiological defects in fish, and the severity increased with increasing duration of exposure, whereas reduction in toxicity in microbially treated groups can be analysed for aquacultural purposes owing to their lesser toxic nature.