Effects of subchronic exposure to microcystin-content in the crude extract of Radiocystis fernandoi on the Neotropical fish (Hoplias malabaricus)

MARCELO G. PAULINO; TAVARES, D.; TEREZAN, A.; ROSSI, P.; VENTURINI, F.; BIECZYNSKI, F.; SAKURAGUI, M.; SOUZA, N.; MORAES, G.; GIANI, A.; LUQUET, C.; FERNANDES, J.; FERNANDES, M.

Buenos Aires

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC

Microcystins is toxic to fish. It can accumulate in the fish tissues causing and changes in liver structure. This study evaluated the bioaccumulation potential of the majority microcystins in the crude extract of the cyanobacteria Radiocystis fernandoi cepa R28 on the fish Hoplias malabaricus after subchronical exposure and their effect on the liver by assessing the liver structure and the detoxification process. Fish were intraperitoneally injected with 100 µg MC-LReq kg-1 every 72 hours during 30 days. Biochemical andmorphological biomarkers were used to evaluate the action of toxins, structural and ultrastructural damage and the detoxification mechanisms. The quantification of microcystins on the crude extract and accumulation in muscle and liver were assessed by HPLC-UV and HPLC-MS. The R. fernandoi R28 strain produced mainly theMC-RR and MC-YR that have hepatotoxic potential. There were bioaccumulation of MC-YR and MC-RR in liver and there was not MC accumulation in muscle. The alanine aminotransferase and aspartate activity in plasma and the serine protein phosphatase/threonine PP2A was inhibited in the liver indicating liver damage.Macroscopically occurred changes in the color, texture and liver mass; microscopically the morphology of hepatocytes and intracellular organelles were altered and abundant fibrous tissue disrupted the architecture of the liver parenchyma. Moreover, the inibition of detoxication process was evidenced by decreasing the GSH content and GST activity. In conclusion, the bioaccumulation of the microcystins depends on concentration and body´s defense system for depuration. The changes of the liver biochemical variables and structure evidenced functional impairment of the organ suggesting that the microcystin present in the crude extract of cyanobacteria R. fernandoi (R28 strain) compromise the animal health and may affect growth, reproduction and even survival after long term exposure.