Estudo histológico do fígado e brânquias de Cichla monoculus (perciformes, cichlidae) e Serrasalmus brandtii (characiformes, serrasalmidae) do baixo São Francisco

Abstract

The Lower São Francisco region is located on the border between Sergipe and Alagoas, going from Paulo Afonso (BA). It has a rich ichthyofauna, and despite the numerous problems in the region, mainly due to degradation, damming, and river pollution, fishing is still one of the most important subsistence activities. Because they are sensitive to exposure to chemical products and accumulate pollutants directly through the water, it is important to carry out histological studies on fish organs from Lower São Francisco. The liver and gills can be evaluated in histopathological studies and used as indicators of contamination of aquatic ecosystems. Given the above, the project aimed to analyze the morphology of cells in the liver and gills of Cichla monoculus and Serrasalmus brandtii through histopathological analysis The fish used were collected in the IV Scientific Expedition of Baixo São Francisco, and .issected to remove fragments of livers and gills, and then fixed in 10% formaldehyde and after 24 hours fixed in 70% alcohol and taken to the Aquaculture and Analysis Laboratory. de Água, where histological studies were performed. To perform the analyses, standard protocol procedures for histopathological techniques were used. Then, the material was analyzed and photographed under a microscope. All specimens evaluated showed histopathological alterations in the gills and livers, such as cytoplasmic vacuolation, leukocyte infiltration, the nucleus in the cell periphery, dilation of sinusoidal vessels, and necrosis in the liver, while in the gills, hypertrophy, displacement of the lamellar epithelium, hyperplasia of the lamellar epithelium, complete and incomplete lamellar fusion, the alterations in both organs represent inflammatory processes in an attempt by the organism itself to defend itself against aggressive agents. The protocol for assessing water pollution standardized by Bernet was used to quantify the histopathological changes, in which the pathological lesions are classified into five patterns according to their importance, thus making it possible to develop a graph that shows the average of histopathologies according to the cities. The result revealed a higher frequency of changes in the city of Pão de Açúcar, this may be related to the precarious disposal of sewage in the city as seen in the expedition, it was also possible to verify that the pirambeba presented a higher rate of changes, which may be associated with its carnivorous and benthopelagic habits. The results may be related to anthropic activities such as river pollution through various sources such as the dumping of waste and the use of pesticides by agriculture and livestock that are leached into the river, in addition to the degradation of the riparian forest and periods of low flow, making it difficult to the dilution of contaminants present in the water. The importance of minimizing the use of agrochemicals, public awareness, and effective treatment of city effluents, such as Pão de Açúcar, a city with a precarious sewage treatment system, is becoming increasingly necessary as scientific studies prove an increase in environmental degradation.

Keywords: histopathology, contamination, tucunaré; pirambeba.