Gill Histopathological Modifications in Oreochromis Niloticus Collected in a Lacustre Systems Under Metallurgical Industrial Influence

MAIRA LIMA; IARA SOUZA; SILVIA MATSUMOTO; MAGDALENA MONFERRAN; DANIEL WUNDERLIN; MARISA FERNANDES

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

SETAC Latin America

The demand for natural resources has been growing exponentially since the industrial revolution and increasing of human population. Consequently, the water resources have been under constant pressure as one of the main conditions in the development of the human population. Metals and metalloids occur naturally in the environment, however, due to the anthropogenic needs, these elements have been manufactured and they wastes released in the environment impacting atmosphere, soil, lakes, rivers, and reservoirs. Fish and their gills are suitable bioindicators as they are sensitive to changes in the environment.The gill functions, structure and direct contact with water facilitate the absorption of pollutants, especially under stress conditions. Histopathological analyses are a useful tool to identify the effects of contaminants in water. The present study evaluated histopathological alterations in the Oreochromis niloticus gills collected in two lakes located in industrial metallurgical areas in the state of Espírito Santo, Brazil, and a reference lake located more than 150km from this region. The main pathologies identified in Oreochromis niloticus gills collected in the reference lake were lamellar hypertrophy and congestion. However, lakes under influence of industrial contaminants had a higher incidence and diversity of lesions, such as lamellar hypertrophy, congestion, filament epithelium displacement, filament epithelium hyperplasia, mucosal cell proliferation, lamellar fusion, aneurysms, and necrosis. These gill pathologies are morphological changes resulting from physiological and biochemical changes caused by environmental conditions that can alter thenormal function of the organ. Most injuries arise as defense mechanisms or compensatory mechanisms to adapt the organ to the stressor.