Effects of dietary Pb(II) and tributyltin on neotropical fish, Hoplias malabaricus: histopathological and biochemical findings

Trahira (Hoplias malabaricus) used to investigate the effects of successive Pb(II) or tributyltin (TBT) dietary doses. After 70 days of acclimation, individuals were exposed to 21 μg Pb g−1 or 0.3 μg TBT g−1 (5-day intervals, 14 doses). Two experiments were conducted to investigate the histopathological effects (liver and kidney) and measure the cholinesterase activity (muscle and brain) after Pb(II) or TBT dietary doses. A number of morphological effects were observed in liver, including cytoskeleton disturbance, microautophagy of mitochondria, nuclear damage, and cell death. In kidney, necrosis area, increasing of the neutrophils cell number, changes in melano-macrophage centers, and free macrophages were frequently registered after both Pb(II) and TBT exposures. The cholinesterase activity was inhibited in muscle after 14 doses of Pb(II), but no effects were found in individuals exposed to TBT. In summary, this work is the first to report detailed in vivo toxic effects in tropical fish, H. malabaricus, after dietary sublethal exposure to Pb(II) and TBT.