Accumulation and biochemical effects of microcystin-LR on Patagonian silverside (Odontesthes hatcheri) fed with Microcystis aeruginosa cells

CARLOS MARCELO LUQUET; FLAVIA BIECZYNSKI; VIRGINIA ANGÉLICA BIANCHI

San Diego, SA

Congreso; Experimental Biology 2012; 2012

FASEB

We studied accumulation and biochemical effects of microcystin-LR (MC) in the Patagonian silverside Odontesthes hatcheri after dietary administration of the cyanobacteria Microcystis aeruginosa (load~1.3 μg MC / g fish, incorporated in standard fish food). After 12 h, MC content in liver did not differ between fish fed with crushed or intact cells, demonstrating O. hatcheri’s capacity to digest cyanobacterial cells and also absorb free MC. In a second experiment, fish received crushed toxic cells, non-toxic cells or control feed; MC accumulation was monitored for 48 h. Protein phosphatase 1 (PP1), catalase (CAT) and glutathione S transferase (GST) activities and lipid peroxidation (MDA) were measured in liver and intestine. Methanol-extractable MC was determined by PP1 inhibition assay, total MC (extractable + protein-bound) was measured by Lemieux oxidation - gas chromatography / mass spectrometry. MC accumulated rapidly up to 22.9 and 9.4 μg MC / g in intestine and liver respectively, followed by a decreasing tendency. Protein-bound MC represented 65–98 % of total MC in both tissues. CAT and GST activities and MDA were significantly increased by MC in liver, but not in intestine. We conclude O. hatcheri is able to digest cyanobacteria, accumulating MC mostly bound to proteins. This could have implications for aquaculture and trophic chain toxic transference. Grants: CONICET PIP 0282, ANPCYT PICT 00214