Branchial histopathological study of Brachyplatystoma rousseauxii (Castelnau, 1855) in the Guajará bay, Belém, Pará State, Brazil - DOI: 10.4025/actascibiolsci.v32i1.4800

Abstract

This work analyzes the morphological alterations in Brachyplatystoma rousseauxii gills and evaluates whether this species can be considered an environmental monitoring biomarker of Guajará Bay. Sampling was carried out in four areas around Belém, Brazil, in four annual periods: dry/wet season, wet season, wet/dry season and dry season. Water pH, temperature and suspended material were evaluated. A total of 36 specimens were collected. The second right gill arch of each animal was removed and immediately fixed and processed for histopathology analysis with light microscopy. The physicochemical analysis of the water during the study period showed slight acidity, temperature and material in suspension within normal levels. Histopathological analysis of the gills from 14 individuals from area I presented no alterations, and only 2 individuals from this area presented some significant type of alteration. In contrast, all individuals captured in areas II, III, and IV presented at least one of the following alterations: aneurism-like alterations, epithelial elevation, infiltration, cell proliferation and cell hypertrophy. Based on the gill histopathological analysis, this organ is considered a good biomarker and the native species B. rousseauxii could be used as a bioindicator for environmental monitoring.