Lactate dehydrogenase and malate dehydrogenase of Astyanax bimaculatus (lambari) from Una River basin as biomarkers of environmental impact

Fish spend their whole life cycle in water and receive the influence of its physico-chemical and biological components over time. The activities of lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) of aquatic organisms can be altered by pollutants in the water. The aim of this study was to determine whether the activities of LDH and MDH in the gills and liver of Astyanax bimaculatus (lambari do rabo amarelo or Two Spots Astyanax in English), can be used as biomarkers of environmental impact in the Una River (SP) Basin. The lambaris for these studies were collected from three water bodies of this basin designated as p1 (Itaim River), p2 (stream by the road to the Municipality of Remédios) and p3 (lake on the road to the Municipality of Dr. José Luiz Cembranelli). The gills and liver were homogenized and this material was then centrifuged and the supernatant was used for LDH and MDH activity assays using the spectrophotometric method, which determined oxidation rate of NADH. The activities of hepatic LDH and MDH and gill MDH were not statistically different in the lambaris collected at the three sites. In the gill tissue, LDH activity of lambaris from p3 was lower than that from p1.This inhibition of LDH in lambaris from p3, as well as the inferior quality of water there, suggest the occurrence of pollutants in this water. It is concluded that the LDH of lambari gills has potential for use as a biochemical marker of environmental impact in the Una River.

Biomonitoring; enzymes; pollution