Comparison of biomarker responses following one dose of benzo-a-pyrene administered to three native Australian fish species

Abstract

The Australian native fish pink snapper (Pagrus auratus Forster) is currently used as a bioindicator species for laboratory and field studies, but is often unavailable from hatcheries, or collected in limited numbers in the field. Consequently, mulloway (Argyrosomus hololepidotus Lacepede) and barramundi (Lates calcarifer Bloch), two Australian native fish species, were tested in an exploratory study as potential bioindicator surrogates to pink snapper. Experimental fish were i.p. injected with benzo(a)pyrene (BaP), a well known biomarker inducer in fish, at a dose of 1.0f. µg/g of fish. Physiological indices i.e. condition factor (CF) and liver somatic index (LSI) and a suite of biomarkers including ethoxyresorufin-0-deethylase (EROD) activity, biliary metabolites, serum sorbitol dehydrogenase (SOH), DNA damage (Comet assay) and heat shock proteins HSP 70 were explored in the three test species. Mulloway and barramundi showed a higher response in biliary metabolite levels than pink snapper, while pink snapper showed a higher EROD induction potential relative to mulloway and barramundi. Mulloway appeared to be sensitive to hepatotoxicants, as the chemical injury sustained by the liver resulted in the release of SOH in the bloodstream of this species. All three species were significantly responsive to DNA damage. When injected with BaP, the three species showed similar response for CF, LSI and HSP 70. Initial results indicate that mulloway and barramundi are suitable surrogate bioindicator species for pink snapper in relation to exposure to BaP.