HISTOPATHOLOGICAL EVALUATION OF THE LIVER OF Brachyplatystoma rousseauxii (CASTELNAU, 1855) FROM GUAJARA’S BAY, BELÉM, PA

Abstract

The species Brachyplatystoma rousseauxii is one of the most important economic resources of the Amazon region. The objective of the present work was to analyze the histopathology of the liver of B. rousseauxii and to indicate this species as a biomonitor of the environmental quality of the Guajará Bay. Samples were collected in four areas: a control area and three areas identified as discharge sites of solid and liquid wastes. Sampling was carried out in four season periods: dry/wet season, wet season, wet/dry season and dry season. The number of collected specimens was 36. The fishes were submitted to biometry after catching. They presented mean total length of 33.45 cm (±7.72), total weight of 239.21 g (±135.24), and liver weight of 1.22 g (±0.56). Liver fragments were processed for light microscopy analysis. Histopathologic analysis demonstrated that 70% of the fish presented hepatitis, inflammation, fatty degeneration, and congestion, and that 30% presented well-organized liver structures, and they were considered healthy. The hepatic changes observed and the number of specimens collected suggest that the environmental quality of the Guajará Bay is affected and that the species B. rousseauxii  is probably adapted to the areas where there are waste discharges.

KEY WORDS: Amazonian biome, biomonitor, liver, histopathology, fish.