GENOTOXIC AND HISTOPATHOLOGICAL BIOMARKERS OF FOUR FISH SPECIES FROM THE MIDDLE SÃO FRANCISCO RIVER WITH DIFFERENT FEEDING HABITS

Abstract

We compared variations in the occurrence of micronuclei (MN), morphonuclear alterations (AMN), and the presence of various liver damages among four fish species, Salminus franciscanus (carnivorous), Leporinus obtusidens (omnivorous), Myleus micans (herbivorous), and Prochilodus argenteus (iliophagous-detritivorous), occupying different trophic levels in an area of ​​the middle São Francisco River, Januária, Minas Gerais. We hypothesized that (i) fish from different trophic levels present varying amounts of MN and AMN, as these damages are related to the presence of environmental contaminants, and (ii) fish from different trophic levels show multiple liver damages, since the liver is an important organ for the purification of organisms, reflecting the presence of aquatic contaminants. Cytogenetic analyses were performed using the MN test and histopathological analyses with photomicrographs of liver tissues. Species were ranked using Principal Component Analysis (PCA) based on genetic alterations and liver damage. Principal axis scores were compared using Generalized Linear Models (GLM) with Gaussian distribution. Significance was verified with ANOVA (F-test), followed by contrast analyses to identify statistical variations between groups. Our results indicated that P. argenteus presented the highest number of MNs, while M. micans and S. franciscanus had the highest quantities of AMNs. S. franciscanus and L. obtusidens were the most affected by degenerative liver lesions. Necrosis, a cell death lesion, had the highest score in P. argenteus. These findings indicate a strong correlation between cytogenetic and histopathological damage indices and the trophic levels occupied by the evaluated fish species.