Adriana Regina Chippari-Gomes

Transportation of juvenile tambaqui (Colossoma macropomum) in a closed system

The objective of this study was to investigate the effect of density, duration and the use of additives to the water during the transportation of juvenile tambaqui (Colossoma macropomum) and use of this data to establish a safe transportation protocol for the species. The tested products and dosages were: salt (1000, 2000 and 3000 mg/L), gypsum (100, 300 and 500 mg/L) and benzocaine (10, 20 and 30 mg/L). Fish were transported in closed systems (plastic bag) at different densities and time periods of up to 24 h. Fish survival (FS) and water quality parameters were monitored immediately after transportation. The remaining fish were kept in floating cages in order to evaluate mortality which occurred up to 96 h after transportation (S96). The best fish density, additives dosages and time period of the transportation was estimated with a general linear model. The effect of the condition factor on FS and S96 was also evaluated. As expected, FS and S96 were significantly related to time and density. FS but not S96, were also were significantly related to treatment. FS with gypsum treatment was not different from controls and FS with table salt and benzocaine treatments were significantly reduced. The condition factor was not related to either FS or S96. FS was inversely correlated with carbon dioxide concentration. It was concluded that the additives did not improve fish transportation survival. Linear models were developed to predict the best transportation densities as a function of time.

Ion fluxes and hematological parameters of two teleosts from the Rio Negro, Amazon, exposed to hypoxia

The aim of this study was to describe the effect of hypoxia on whole body ion fluxes and hematological parameters in two Amazonian teleosts: Serrasalmus eigenmanni and Metynnis hypsauchen. The increase of Na+ and Cl- effluxes on M. hypsauchen exposed to hypoxia may be related to an increase of gill ventilation and effective respiratory surface area, to avoid a reduction in the oxygen uptake, and/or with the decrease of pHe, that could inhibit Na+ and Cl- transporters and, therefore, reduce influx of these ions. Effluxes of Na+ and Cl- were lower in hypoxia than in normoxia for S. eigenmanni, possibly because in hypoxia this species would reduce gill ventilation and oxygen uptake, which would lead to a decrease of gill ion efflux and, consequently, reducing ion loss. The increase on hematocrit (Ht) during hypoxia in M. hypsauchen probably was caused by an increase of the red blood cell volume (MCV). For S. eigenmanni the increase on glucose possibly results from the usage of glucose reserve mobilization. Metynnis hypsauchen showed to be more sensitive to hypoxia than Serrasalmus eigenmanni, since the first presented more significant alterations on these osmoregulatory and hematological parameters. Nevertheless, the alterations observed for both species are strategies adopted by fishes to preserve oxygen supply to metabolizing tissues during exposure to hypoxia.

Lethal temperatures for Rhamdia quelen larvae (Pimelodidae)

The lower and upper lethal temperatures (LT50) of R. quelen larvae were determined. The larvae were obtained from two spawning periods with hatching temperatures of 21 and 26oC respectively. Larvae were placed in tanks at which the temperatures were either increased 1oC every 15min, or reduced 1oC every 20min until larval movement ceased. This temperature was then maintained for 96h. Minimum mortality (29.0 ± 1.5%) was observed in the larvae held at hatching temperatures. The lower LT50 were 15.01 and 16.72oC, and the upper LT50 were 29.25 and 27.83oC for the larvae hatching at 21 and 26oC, respectively. Thus, apparently there is no difference with relation to temperature change tolerance between larvae hatched in both temperatures.

Acute copper toxicity in juvenile fat snook Centropomus parallelus (Teleostei: Centropomidae) in sea water

Tres experimentos foram realizados para avaliar o acumulo e toxicidade aguda do cobre (Cu) em juvenis de robalo-peva Centropomus parallelus. O primeiro experimento foi realizado para determinar a concentracao letal (96h-CL50) de Cu. O segundo experimento foi realizado para avaliar os efeitos de concentracoes subletais de Cu (0,47 e 0,94 mg/L), enquanto o terceiro permitiu testar a capacidade de recuperacao dos peixes expostos a concentracoes subletais do Cu e posteriormente mantidos em agua do mar sem acrescimo de Cu. O valor de LC50 encontrado para o Cu foi de 1,88 mg/L. Os peixes expostos as concentracoes subletais de Cu mostraram um acumulo significativo nas brânquias em relacao ao controle em 96 h de exposicao (0,43 µg/g Cu). Nenhuma diferenca significativa foi observada entre os peixes expostos a 0,47 mg/L de Cu (1,09 µg/g) e 0,94 mg/L de Cu (1,26 µg/g). A exposicao (24 e 96 h) para as concentracoes subletais de Cu induziram danos no DNA. Os resultados mostram que a exposicao aguda a concentracoes subletais induz o acumulo de Cu e danos ao DNA nas brânquias dos peixes, onde estes efeitos sao recuperados apos 240 h em agua do mar sem adicao de Cu.

Acute toxicity of the water-soluble fraction of diesel in Prochilodus vimboides Kner (Characiformes: Prochilodontidae)

O oleo diesel pode ser uma fonte de contaminacao em ambientes aquaticos, principalmente como resultado de derrames acidentais. Foram avaliados os efeitos da fracao soluvel do oleo diesel (FSO) em Prochilodus vimboides. Os peixes foram expostos a tres diferentes diluicoes da FSO por ate 96 horas e comparados com um grupo controle. Os danos nos fragmentos de DNA foram analisados utilizando o ensaio Cometa. A presenca de anormalidades nos eritrocitos foi avaliada pelo teste do micronucleo. A atividade da Aspartato aminotransferase (AST) e alanina aminotransferase (ALT) e da acumulacao de cobre nas brânquias tambem foram analisados. Os peixes expostos por 96 h tiveram maiores taxas de danos do que aqueles expostos por 24 h. Nao houve diferenca significativa quanto a presenca de micronucleos entre os peixes expostos e controle e entre 24 e 96 h exposicoes. Para AST, nao foi observada diferenca significativa entre as amostras coletadas em dois tempos de exposicao. Os peixes expostos a uma diluicao de 1:100 do FSO apresentaram maior atividade da enzima ALT do que os peixes do controle apos um periodo de exposicao de 24 horas. Nao houve bioacumulacao de cobre nas brânquias. Os efeitos genotoxicos nas celulas foram os mais evidentes em P. vimboides durante a exposicao aguda a FSO.

Effects of manganese on fat snook Centropomus parallelus (Carangaria: Centropomidae) exposed to different temperatures

This study evaluates the effects of exposure to manganese (Mn2+) for 96 hours at two different temperatures (24 and 27°C) on juveniles of Centropomus parallelus through the activities of glutathione S-transferase (GST) and catalase (CAT), micronuclei test (MN) and comet assay. The GST activity did not show any significant difference between the groups exposed to Mn2+ and the respective control groups; in contrast, a major increase in the CAT activity was observed at 27°C in the group exposed to Mn2+ compared to the control group. The genotoxic analyses showed that in all animals exposed to Mn2+, the number of red cells with micronuclei increased significantly compared to the respective control groups. There was also a significant increase in the incidence of DNA damage in the groups exposed to Mn2+. At a temperature of 24oC, animals exposed to Mn2+ had more DNA damage than those at 27°C. It is likely that the increase in temperature can also induce oxidative stress. Thus, we conclude that manganese is toxic to the fat snook juveniles, causing genotoxic damage, and when associated with an increase in temperature, manganese can also provoke an increase in oxidative stress.

The effects of subchronic exposure to copper in fat snook (Centropomus parallelus).

Anthropogenic processes affect different communities through the release of contaminated effluents into water bodies. Copper can be found in the effluents of most industrial processes and in other effluent types. The fat snook Centropomus parallelus, found from Florida in the United States to southern Brazil, is of great economic importance and is used as a food resource near the coast. This study aimed to determine the effects of copper on C. parallelus. The fish were exposed for 30 or 60 days to treatments of 0, 13 and 26μgCuL(-1). Genotoxic effects of copper were observed in the micronuclei, especially in individuals exposed to higher concentrations. Copper exposure also had a negative effect on the growth of fat snook individuals. Compared to the control group without the addition of metal, an accumulation of metal was observed in the gills of exposed fish, an effect that was not found in the muscle.

Specialized metabolism and biochemical suppression during aestivation of the extant South American lungfish — Lepidosiren paradoxa

Lepidosiren paradoxa (pirambóia) is the single representative of Dipnoan (lungfish) in South America. This species is considered a living fossil, in spite of some reports describing this fish as having a very specialized life style. It aestivates during the dry season, and has developed metabolic adaptations to cope with both flooding and drought. The literature describing its tissue ultra-structure shows high glycogen stored in the muscle, suggesting a strong dependence on anaerobic glycolysis. The present paper reports tissue enzyme levels of LDH, MDH, and CS, and isozymic tissue distribution of LDH, MDH, ADH, PGI, SOD, and PGM of 7 aestivating specimens from Lago do Canteiro in the Amazonas River. Animals were caught while burrowed in mud during the aestivation period. Our findings reveal high anaerobic capacity of both skeletal and heart muscles, even during the aestivation period, when enzymes showed suppressed levels compared to those of non-aestivating animals (data from the literature). Isozymic patterns suggest loss of duplicate condition in most analyzed loci, a characteristic that occurs mainly in higher vertebrate categories. These data indicate that, compared to the fish group, lungfish may be considered advanced, despite retaining primitive morphological characters.

Temperature affects the hypoxia tolerance of neotropical Cichlid Geophagus brasiliensis

Oxygen and temperature are the most limiting factors in aquatic environments. Several species are exposed to variations of these factors in water because of physical, chemical and biological processes. The objective of this study was to evaluate the metabolic profile and the tolerance to the hypoxia of Geophagus brasiliensis exposed to changes in temperature and oxygen availability. The fish were exposed to 20 and 90% of oxygen saturation combined with different temperatures (20°, 24° and 28° C) for 8 h. Hepatic and muscular glycogen, as well as the activities of lactate dehydrogenase (LDH), malate dehydrogenase (MDH), citrate synthase (CS) and their ratios were evaluated. Both glycogen and MDH activity showed a significant difference in the liver. While CS showed increased activity only in the heart. The increase in LDH activity in the white muscle shows the importance of the anaerobic pathway as energy source in this tissue. The MDH / LDH ratio increased in all tissues, while CS / LDH increased in the liver and decreased in the heart. Based on the results of the present study it may be concluded that this species used the anaerobic metabolism as the main strategy for hypoxia tolerance.

Genotoxic, biochemical and bioconcentration effects of manganese on Oreochromis niloticus (Cichlidae)

Manganese and iron were found at high concentrations (3.61 mg/L and 19.8 mg/L, respectively) in the water of the Rio Doce after the dams of Fundão and Santarém broke in Mariana/MG (Brazil). These same metals were found in fish and crustacean muscle (15 mg/kg and 8 mg/kg wet weight, respectively) in the specimens collected near the Rio Doce’s outfall. Due to the variation in Mn concentration found in the lower Rio Doce, this study aimed to determine the effects of Mn in Oreochromis niloticus, at the concentrations allowed by CONAMA, and in concentrations found in the Rio Doce after the dams broke. The animals were exposed to the following dissolved concentrations: control group (0.0 mg/L), 0.2; 1.5 and 2.9 mg/L manganese for 96 h. In addition, a positive control was conducted, injecting intraperitoneally with cyclophosphamide (at 25 mg/kg). These exposures caused significant erythrocyte micronucleus formation in the organisms exposed to the highest concentration, as well a significant increase in the DNA damage index of erythrocytes from organisms exposed to 1.5 mg/L and 2.9 mg/L treatments. The glutathione S-transferase enzyme activity also showed a significant increase in the liver of the organisms exposed to 2.9 mg/L. However, catalase activity increased significantly in the gills of the animals exposed to all concentrations of manganese that were tested. Manganese bioconcentrated in greater quantities in the liver than the gills. Thus, manganese causes significant damage to genetic material, generates nuclear abnormalities, activates the body’s detoxification system and can accumulate in animal tissue.