Use of biomarkers in Nile tilapia (Oreochromis niloticus) to assess the impacts of pollution in Bolgoda Lake, an urban water body in Sri Lanka

Abstract

The present study reports the first analysis of water pollutants in Sri Lankan waters using a suite of biomarkers in Nile tilapia (Oreochromis niloticus) residing in Bolgoda Lake which receives urban, industrial and domestic wastes from multiple sources. The fish were collected from the lake in the dry period (April 2005) and wet periods (September 2005, October 2006) and the levels of biomarkers viz. hepatic ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST), metallothioneins, biliary fluorescent aromatic compounds, brain and muscle cholinesterases (ChE) were compared with those of the laboratory reared control fish and the fish obtained from a less polluted water body, Bathalagoda reservoir (reference site). The results revealed that biomarker levels of the fish collected from the reference site were not significantly different from the controls. Hepatic EROD and GST activities in fish from Bolgoda Lake were induced 4.2-16.6 folds and 1.4-3.3 folds respectively compared with the control fish. Analysis of bile in the lake fish revealed recent uptake of naphthalene, pyrene and benzo(a)pyrene type polycyclic aromatic hydrocarbons (PAHs). The induction of EROD activities in feral fish reflects the exposure of fish to aryl hydrocarbon receptor agonists including PAHs present as pollutants in the Bolgoda Lake. Cholinesterase activity in the fish inhabiting one sampling site of Bolgoda Lake was lower (22-40% inhibition) than the activity measured in the control fish indicating the presence of anticholinesterase pollutants in the area. Hepatic metallothionein levels in the lake fish were higher (1.9-3.2 folds) in comparison to the controls indicating metal exposure. The results support the potential use of these biomarkers in Nile tilapia in assessing pollution in tropical water bodies.

Assessment of biological effects of pollutants in a hyper eutrophic tropical water body, Lake Beira, Sri Lanka using multiple biomarker responses of resident fish, Nile tilapia (Oreochromis niloticus)

“…The hepatic GST activities in the control Nile tilapia used in the present study were higher than the values reported for the control fish used in our earlier study (Pathiratne et al 2009). This may be due to the use of higher temperature condition (30°C) of the assay medium in this study to reflect the natural temperature conditions in the Lake.…”

“…The ChE activities in the brain and muscle homogenates of individual fish were determined at 25°C using acetylthiocholine iodide as the substrate following the method of Ellman et al (1961) as described earlier (Pathiratne et al 2008). Microsomal and cytosolic fractions of liver tissues were prepared by differential centrifugation (Pathiratne et al 2009). GST in the liver cytosol fraction was measured at 30°C by following the conjugation of glutathione at 340 nm using 1-chloro-2,4-dinitrobenzene as the substrate (Habig et al 1974).…”

Modulation of ethoxyresorufin O-deethylase and glutathione S-transferase activities in Nile tilapia (Oreochromis niloticus) by polycyclic aromatic hydrocarbons containing two to four rings: implications in biomonitoring aquatic pollution

“…Nile tilapia (Oreochromis niloticus) which is a widespread food fish species in tropical countries has been suggested as a test species for biomonitoring of aquatic pollution in tropical environments (Gold-Bouchot et al 2006;Pathiratne et al 2009). Objective of this study was to compare the effects of commonly occurring five selected PAHs containing two to four fused aromatic rings viz.…”

Enzymatic Activity in the Gastrointestinal Tract of Pimelodus maculatus (Teleostei, Siluriformes) in Two Neotropical Reservoirs with Different Trophic Conditions

“…In this study, gastrointestinal and hepatic activities for trypsinlike and chymotrypsin-like peptidases and for β-glucosidase were relatively with low variation among the specimens. This was relevant, since the biochemical parameters such as enzymatic activities were usually affected by the pollutants ( Van der Oost et al 2003;Pathiratne et al 2009;Kuz'mina et al 2013). Thus, before specific comparisons between the two reservoirs, one must point out that these hydrolases are promising biomarker for future studies given the acceptable low intraspecific variations and the easy assaying of their activities with chromogenic or natural substrates.…”