Multi-level Integrative Biomarker Responses in Freshwater Teleostean Fishes Exposed to Almix Herbicide

Abstract

In the present study, multi-level integrative biomarker responses (multi-level IBR) were studied to evaluate the toxicological effects of Almix herbicide towards Indian teleosts, namely Anabas testudineus, Heteropneustes fossilis and Oreochromis niloticus under laboratory (66.7 mg/L) and field (8 g/acre) conditions (30 days). At physiological level, condition factor (CF) displayed significant increase (p < 0.05) under both conditions, while liver somatic index (LSI) exhibited significant increase under field. Haematological parameters were significantly induced (enhanced and/or reduced), when compared with control value under both conditions in concerned fish species, although responses were species-specific. At molecular level, micronucleus (MN) study showed enhanced erythrocyte nuclear abnormalities (ENA) under both conditions; response was more severe under laboratory study [H. fossilis (0.37 +/- 0.08) > O. niloticus (0.31 +/- 0.06) > A. testudineus (0.23 +/- 0.03)]. However, in field study, the degree of ENA were H. fossilis (0.14 +/- 0.03) > O. niloticus (0.11 +/- 0.04) > A. testudineus (0.09 +/- 0.03). Additionally, multi-level IBR index indicating the degree of severity as of H. fossilis (6.97-fold) > A. testudineus (threefold) > O. niloticus (twofold) under laboratory condition, while in field study, it was H. fossilis (4.98-fold) > A. testudineus (twofold) > O. niloticus (1.67-fold). However, higher IBR index value in laboratory study indicated more severe adverse effects of Almix intoxication than field study, although varied multi-level IBR index under different conditions suggested the different contamination level. Therefore, these findings infer that multi-level IBR index might serve as a useful tool for quantitative monitoring of toxicological effects.