Profile of micronucleus frequencies and DNA damage in different species of fish in a eutrophic tropical lake

Abstract

Lake Paranoá is a tropical reservoir for the City of Brasilia, which became eutrophic due to inadequate sewage treatment associated with intensive population growth. At present, two wastewater treatment plants are capable of processing up to 95% of the domestic sewage, thereby successfully reducing eutrophization. We evaluated both genotoxic and cytotoxic parameters in several fish species (Geophagus brasiliensis, Cichla temensis, Hoplias malabaricus, Astyanax bimaculatus lacustres, Oreochromis niloticus, Cyprinus carpio and Steindachnerina insculpita) by using the micronucleus (MN) test, the comet assay and nuclear abnormality assessment in peripheral erythrocytes. The highest frequencies of MN were found in Cichla temensis and Hoplias malabaricus, which were statistically significant when compared to the other species. However, Steindachnerina insculpita (a detritivorous and lake-floor feeder species) showed the highest index of DNA damage in the comet assay, followed by C. temensis (piscivorous). Nuclear abnormalities, such as binucleated, blebbed, lobed and notched cells, were used as evidence of cytotoxicity. Oreochromis niloticus followed by Hoplias malaricus, ominivorous/detritivotous and piscivorous species, respectively, presented the highest frequency of nuclear abnormalities, especially notched cells, while the herbivorous Astyanax bimaculatus lacustres showed the lowest frequency compared to the other species studied. Thus, for biomonitoring aquatic genotoxins under field conditions, the food web should also be considered.

Baseline micronuclei and nuclear abnormalities frequencies in native fishes from the Paraná River (Argentina)

“…Similar results were described in studies carried out with other fish species establishing in situ frequencies (Rodriguez-Cea et al, 2003;Grisolia et al, 2009). The highest baseline MN and NA frequencies were found in the species S. brevipinna.…”

“…Furthermore, this paper provides additional information on similar records of spontaneous MN frequencies reported for fishes by other working groups (Grisolia et al, 2009). This record provides a base for the selection of species as suitable indicators in biomonitoring studies.…”

“…In this way, several studies of biomonitoring in situ in rivers and lakes were accomplished using the micronucleus test with diverse fish species bringing about interspecific variation in baseline frequencies of genetic damage (Grisolia et al, 2009;Rodriguez-Cea et al, 2003). However, researches employing biomarkers in tropical and neotropical freshwater fish from South America are scarce (Rabitto et al, 2005).…”

Cytogenetic toxicity and gonadal effects of 17 α-methyltestosterone in Astyanax bimaculatus (Characidae) and Oreochromis niloticus (Cichlidae)

“…The synthetic androgen MT, widely used as a reference chemical to induce male monosex, is considered an endocrine disrupter in fish (Smith, 1974;Pandian and Sheela, 1995;Ankley et al, 2001;Zerulla et al, 2002;Arslan and Phelps, 2004;Hornung et al, 2004;Pawlowski et al, 2004;Kang et al, 2008;Grisolia et al, 2009). However, few studies have been performed to assess the possible genotoxic effect of MT or to examine any aspect of DNA damage caused by testosterone treatment in organs of intact animals.…”

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations

“…In fish, the combination of micronucleus test (MN), nuclear abnormality test (NA), and the comet assay can be carried out in the same organism to give more consistency to in vivo evaluation of the genotoxicity of environmental pollutants (al-Sabti and Metcalfe, 1995;Grisolia and Starling, 2001;Pacheco and Santos, 2002;Kim and Hyun, 2006;Bolognesi et al, 2006;Grisolia et al, 2009). In this study, Oreochromis niloticus, a target species for MT in fish hatcheries, and Astyanax bimaculatus, a non-target species for MT in hatcheries, were exposed to MT, to evaluate its possible genotoxicity.…”