Eugenol and tricaine methanesulfonate as anhestesics for the pearl cichlid

Anesthesia reduces the handling process duration and prevent fish injuries. The anesthetic effect and ideal concentrations of eugenol and tricaine methanesulfonate (MS-222) were tested for pearl cichlid (Geophagus brasiliensis) juveniles with an average weight of 4.4 g in water at 24ºC. The criterion for determining the optimal dose considered an induction time of one minute. Experiment 1 tested the concentrations of 25, 75, 150 and 300 mg L-1 of eugenol. The best results were obtained at doses of 150 and 300 mg L-1. Experiment 2 aimed to establish a more accurate result by testing the concentrations of 180, 210, 240 and 270 mg L-1, and led to an estimation of 217 mg L-1 of eugenol to induce anesthesia in one minute. Experiment 3 evaluated 200, 300, 400, 500 and 600 mg L-1 of tricaine, of which the concentration of 294 mg L-1 was estimated to induce anesthesia in one minute. No significant differences were observed for recovery times when using either of the anesthetics. No mortality was observed within 24 hours after the experiments for any concentration of the anesthetics. The present study recommends 217 mg L-1 of eugenol or 394 mg L-1 of tricaine for anesthesia of the pearl cichlid.

Multiple biomarkers response in a Neotropical fish exposed to paralytic shellfish toxins (PSTs).

The Alagados Reservoir (Southern Brazil) is used as water supply, and since 2002 there have been reports with a presence of cyanobacterial blooms and cyanotoxins. In order to assess the water quality and the ecological integrity of the reservoir, we evaluated biochemical, genotoxic and osmoregulatory biomarkers in the freshwater cichlid fish (Geophagus brasiliensis) that were exposed to PSTs. The fish were sampled in the Alagados Reservoir in February 2016 (Summer) and were divided in three groups: 1) Reservoir group (RES): fish were collected immediately after sampling; 2) Depuration group (DEP): fish were submitted to the depuration experiment for 90 days in the laboratory; and 3) Reproduction group (REP): fish were kept in the laboratory until the fertilization and the chemical analyses were performed on the offspring (F1 generation). In the RES and DEP the blood, brain, muscle, liver and gills were collected for biochemical, genotoxic and osmoregulatory biomarkers analysis. Our results showed that the fish from the Alagados Reservoir (RES) presented oxidative stress and DNA damage; and after 90 days (DEP), the antioxidant system and DNA damage were recovered. Although PSTs were considered a risk to the ecological integrity of this water body; PSTs concentrations were not found in the tissues of the F1 generation. In addition, the biomarkers used were useful tools to evaluate the effects of environment contamination. Therefore, it is necessary to develop new technologies and monitoring programs in order to reduce cyanobaterial blooms, cyanotoxins and human activities that cause the contamination in aquatic environments.

Sublethal effects of microcystin-LR in the exposure and depuration time in a neotropical fish: Multibiomarker approach.

Eutrophication is an ecological process that results in cyanobacterial blooms. Microcystin-LR is the most toxic variant of microcystins and may cause toxic effects in the organisms, mainly in hepatic tissues. The aims of this study were to use multiple biomarkers in order to evaluate the sublethal effects of a low concentration of MC-LR (1 µg/L) in fish Geophagus brasiliensis by waterborne exposure; and evaluate the depuration of this toxin during 15 days. A group of 30 fish was exposed to 1 µg/L of MC-LR solution for 96 h in a static bioassay. After this time, blood, brain, muscle, liver, gonad and gills were collected from half of the exposed fish group in order to evaluate chemical, biochemical, histological and genotoxic biomarkers. The rest of the fish group was submitted to the depuration experiment with free MC-LR water for 15 days. After this time the same tissues were collected and evaluated using biomarkers analysis. Toxic effects were found mostly in the fish liver from depuration time as alterations on the antioxidant system and histopathologies. The results showed that even low concentrations can cause sublethal effects to aquatic organisms, and cyanotoxins monitoring and regulation tools are required.

Toxicological effects of anthropogenic activities in Geophagus brasiliensis from a coastal river of southern Brazil: A biomarker approach.

This study aimed to assess the water quality of the Perequê River, Porto Belo, Santa Catarina, Brazil, through a biomarker approach in the native fish species Geophagus brasiliensis, and the sediment chemical quantification of the herbicides glyphosate and bentazone used in irrigated rice plantations. This river is used for the public water supply of two municipalities. The first sampling (S1) was in November 2016, in the spring season and the second (S2), in March 2017, in the fall season. In each sampling, two points of the river were analyzed, one upstream of the accumulation dam and the water catchment point for water supply of the Porto Belo WTS (P1), and another downstream (P2) with water, sediment, and fish sampling. Biotransformation, oxidative stress, histopathological and genotoxic biomarkers were analyzed in different tissues. The presence of glyphosate was detected in the sediment (11.7 µg·kg-1) from the upstream point of the water catchment site (P1) in spring. The lower activity of the antioxidant enzyme superoxide dismutase (SOD), as well as the increased damage to renal DNA and hepatic tissue, coincided with the lower muscular and cerebral acetylcholinesterase activities (AChE) at P1, in relation to P2 in the spring season, with a lower rainfall index (81.8 mm3). A seasonal variation was also observed between the spring and fall seasons, in fish responses to biomarkers. Reduction of muscle AChE activity and biotransformation enzymes ethoxyresorufin-O-deethylase and glutathione S-transferase and antioxidant enzymes such as, SOD and glutathione peroxidase, as well as increased brain DNA damage, coincided with the highest number of tissue lesions in the liver and gills in the spring, regardless of the sampling point. The results suggested that the Perequê River is contaminated by xenobiotics and probably herbicides from irrigated rice plantations, indicating damages to the biota and a potential public health risk.

Combined effects of predator odor and alarm substance on behavioral and physiological responses of the pearl cichlid.

Several fish species trigger defensive behavioral responses when exposed to chemical cues that indicate predation risk. In these situations, physiological adjustments are also necessary to prepare the organism for a defensive response and increase survival odds. Chemical cues may be derived from predator odor or injured conspecifics. However, little is known about the effects of both cues combined. Therefore, our study evaluated the combined effects of predator odor (PO) and conspecific alarm substance (CAS) on the anti-predatory responses of the pearl cichlid (Geophagus brasiliensis). We set 4 experimental conditions 1) PO + CAS; 2) PO + Distilled Water (DW); 3) DW + CAS; and 4) DW + DW (negative control). Fish exposed to DW + CAS had values of ventilation rate and feeding latency significantly higher than when exposed to the other conditions, which yielded similar responses for both variables. Our data show that the combination of PO + CAS interfered with pearl cichlid behavior and physiology since it abolished CAS defensive responses. These results show that CAS plays an important role on the defensive responses of pearl cichlids, while PO does not, given that fish did not respond to PO by itself. Our findings point to different cue-specific strategies in pearl cichlids when dealing with different chemical cues that indicate predation risk.

The accumulation dynamics, elimination and risk assessment of paralytic shellfish toxins in fish from a water supply reservoir.

Paralytic shellfish Toxins (PSTs) or saxitoxins are neurotoxins that block the neural transmission by binding to the voltage-gated sodium channels in the nerve cells. There are >50 analogues described, which could be biotransformed into a molecular form of greater or lesser toxicity. The Alagados Reservoir is used for water supply, and persistent cyanobacterial blooms as well as PSTs concentrations have been found in this water body since 2002. The aims of this study were to quantify the concentrations of PSTs in the water and fish samples from the Alagados Reservoir. In addition, we evaluated the elimination of PSTs for 90 days in fish and estimated the potential risk to human health. Water and fish samples were collected from the reservoir. For the water samples the phytoplankton and chemical analyses were carried out. Fish were divided into two sample times: Field Samples (FS) and Elimination Experiment Samples (EES), which were maintained for 90 days in filtered and dechlorinated water. For chemical analysis, the muscles of FS were collected on the fish sampling day and the muscles and feces of EES were collected at 7, 15, 30, 45, 60, 75 and 90 days. PSTs concentrations were present in water and fish samples, and they were estimated as a potential risk to humans; mainly for children. In addition, toxins were accumulated, biotransformed to other analogues and excreted by the fish. However, after 90 days, the toxins were still present in the water and fish muscle. Therefore, PSTs can remain for a long period in water, and fish can be a carrier of these neurotoxins. New approaches of monitoring and management are necessary in the actual global context of cyanobacteria and cyanotoxins.

Composition, abundance and biomass of a fish assemblage in a southern Brazilian coastal stream during polyhaline/euhaline condition / Composição, abundância e biomassa de uma assembléia de peixes em um arroio costeiro do sul do Brasil durante condição polihalina/euhalina

Abstract: The coastal streams of southernmost Brazil, Rio Grande do Sul state, are marked by a period of regular marine intrusion resultant from intense oceanic winds. In the present study we aimed to investigate the species composition, abundance and relative biomass of the ichthyofauna in the lower stretch of a coastal stream during summer, a period of regular marine intrusion. Estreito is a coastal hydrological complex composed by lakes, swamps and a perennial stream, located at the central-south portion of the coastal plain of Rio Grande do Sul state. During the summer of 2018, the ichthyofauna of lower Estreito stream was sampled by beach hauls applied in 17 random points distributed in a stretch of ca. 2km. Measurements at the sampled stretch revealed salinities between 19.3 to 31.3 ppt, characterizing the studied system as polyhaline/euhaline during summer. The sample of 4,533 specimens revealed the occurrence of 20 species, being the great majority marine-dwelling. The most abundant species were the anablepid Jenynsia lineata (70.3%), the cichlid Geophagus brasiliensis (19.3%) and the the mugilid Mugil curema (7.5%). The highest relative biomass was recorded for J. lineata, followed by M. curema and G. brasiliensis. The dominance of marine-dwelling species in the assemblage composition and the high abundance of limnic-estuarine J. lineata corroborate previous studies conducted in other washouts of Rio Grande do Sul.

Resumo: Os arroios costeiros do extremo sul do Brasil, estado do Rio Grande do Sul, são marcados por um período de regular intrusão marinha resultante de intensos ventos oceânicos. No presente estudo nós tivemos como objetivo investigar a composição de espécies, abundância e biomassa relativa da ictiofauna no trecho inferior de um arroio costeiro durante o verão, período de regular intrusão marinha. Estreito é um complexo hidrológico costeiro composto por lagoas, pântanos e um arroio perene, localizados na porção centro-sul da planície costeira do Rio Grande do Sul. Durante o verão de 2018, a ictiofauna do baixo arroio Estreito foi amostrada por arrastos de praia aplicados em 17 pontos aleatórios distribuídos em um trecho de cerca de 2 km. Medidas no trecho amostrado revelaram salinidades entre 19.3 e 31.3 ppt, caracterizando o sistema estudado como polialino/euhalino durante o verão. A amostra de 4.533 espécimes revelou a ocorrência de 20 espécies, sendo a grande maioria habitantes marinhos. As espécies mais abundantes foram o anablepídeo Jenynsia lineata (70,3%), o ciclídeo Geophagus brasiliensis (19,3%) e o mugilídeo Mugil curema (7.5%). A maior biomassa relativa foi registrada para J. lineata, seguido por M. curema e G. brasiliensis. A dominância das espécies marinhas na composição da assembléia e a alta abundância da espécie límnica-estuarina J. lineata corrobora estudos prévios conduzidos em outros sangradouros do Rio Grande do Sul.

Induced CYP1A activity and DNA damage in fish from the middle Paraíba do Sul River basin, southeastern Brazil / Atividade induzida de CYP1A e danos de DNA em peixes do trecho médio da bacia do rio Paraíba do Sul, sudeste do Brasil

The Paraíba do Sul River (PSR) drainage basin in Southeastern Brazil covers one of the most industrialized and densely populated regions of the country. The impact of chemical contamination on the PSR basin seems to be more pronounced in its middle reach where a number of potentially polluting plants are located. In this study, we used hepatic EROD activity - a biomarker of exposure to CYP1A-inducing pollutants (e.g. PAHs, PCDD/Fs, PCBs) - and the incidence of micronucleated erythrocytes (Mn) in the peripheral blood - a biomarker of effects of DNA-damaging agents (e.g. PAHs) - to evaluate the effects of pollution on two native fish species, Geophagus brasiliensis and Pimelodus maculatus. Results showed that the incidence of Mn and EROD in G. brasiliensis and P. maculatus from the two most downstream sites (Três Rios Town and Piabanha River) were markedly higher than the incidence of Mn and EROD recorded in fish from the most upstream site (Funil Reservoir). Our findings are consistent with the view that CYP1A-inducing activity and increased DNA-damage are found in fish caught in sampling sites located downstream of the stretch where there are several industries that are potential sources of PAHs and CYP1A-inducing contaminants.

O rio Paraíba do Sul (RPS) drena uma das mais industrializadas e densamente povoadas áreas do sudeste do Brasil. O impacto de contaminação química no RPS parece ser mais pronunciado no segmento médio da bacia onde se localiza grande número de indústrias potencialmente poluidoras. Neste estudo, foi avaliada a atividade hepática EROD – um biomarcador de exposição a poluente indutores da CYP1A (e.g. HAPs, PCDD/Fs, PCBs) – e a incidência de eritrócitos micronucleados (Mn) no sangue periférico – um biomarcador de efeitos de agentes de danificação do DNA- (e.g. HAPs) – para avaliar o efeito de poluição sobre dois peixes nativos, Geophagus brasiliensis e Pimelodus maculatus. Os resultados apresentaram que a incidência de Mn e EROD em G. brasiliensis e P. maculatus nos dois locais no trecho mais baixo (Três Rios e rio Piabanha) foi marcadamente mais elevada do que a incidência e a atividade EROD registradas em peixes dos locais mais à montante (reservatório do Funil). Estes resultados são consistentes com a visão de que atividade indutora de CYP1A e elevadora de danos no DNA são encontradas em peixes capturados em locais abaixo do trecho onde grande número de indústrias são potenciais fontes de poluição de indutores de contaminantes HAPs e CYP1A.

How and where to perform biomonitoring studies: different levels of toxic metal pollution are detected in the Alagados Reservoir in Southern Brazil.

The Alagados Reservoir located in the Brazilian city of Ponta Grossa is used to supply water for human consumption but is impacted by toxic metals. The current study combined chemical, biochemical, and multivariate analyses to determine the bioavailability of toxic metals at three sites (AL-A, AL-B, and AL-C) within the Alagados Reservoir. Metal bioaccumulation was analyzed in the liver, gills, and muscle tissue of a native fish species (Geophagus brasiliensis), and neurotoxicity, xenobiotic metabolism, and oxidative stress were evaluated using biochemical biomarkers. Additionally, histopathological studies were performed on the gills and the liver using scanning electron microscopy (SEM) and conventional light microscopy (LM), respectively. Overall, the bioaccumulation of metals, biomarkers of oxidative stress, and melanomacrophage counts indicate that the AL-C and the AL-A sites are the most and least affected by metals, respectively. The AL-B site presented the lowest acetylcholinesterase enzyme activity, a finding which was probably associated with the agricultural activities around this area of the reservoir. The biomarkers clearly revealed that toxic metals negatively affect all three sites studied herein and that human activity is the major source of pollutants. Despite the existence of different pollution levels within the Alagados Reservoir, it is still used as a human water supply.

Neurotoxins in a water supply reservoir: An alert to environmental and human health.

Reservoirs are important source of power generation, recreation, and water supply. Nevertheless, human activities have favored the bloom of toxic cyanobacteria in many reservoirs, which has resulted in environmental, social, and economic problems. This study aims to evaluate the water quality of a reservoir in South Brazil through the analysis of cyanobacteria and cyanotoxins PSTs (Paralytic Shellfish Toxins) and biomarkers of environmental contamination in fish. For this purpose, water samples and fish (Geophagus brasiliensis) (Perciformes: Cichlidae) were collected from September 2013 to May 2014. The fish G. brasiliensis were separated in two groups. The first one "site group" was euthanized after the sampling and their weight and length were measured. The blood, brain, muscle and liver were collected for chemical, biochemical and genetics biomarkers analysis. The second group "depuration group" was submitted to depuration experiment for 40 days in clean water. After that, the same procedures as for the first group were carried out. Cylindrospermopsis raciborskii was the dominant cyanobacteria found in the reservoir, and it showed a density above the recommended limit by Brazilian legislation of 20,000 cells/mL. Results showed that the fish accumulate PSTs in the Reservoir and these were not eliminated after 40 days. The biochemical and genotoxic biomarkers showed a significant difference between "site groups" and "depuration groups", which suggests a recovery of the antioxidant system and a reduction of cellular damage after 40 days in clean water. In conjunction with results reported earlier by others, Alagados Reservoir, in South Brazil, appears to have a persistent contamination of cyanotoxins. Moreover, the mixture of contaminants which may be present in the water body can explain the seasonal differences in fish at the sampled points.

Description of the karyotype of Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae) / Descrição do cariótipo de Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae)

This study described the karyotype of Geophagus cf. proximus. Specimens were collected in Água Preta Lake, Parque Ambiental de Belém, Pará State, Brazil. The karyotype were 2n = 48 chromosomes (FN = 60: 12M/SM+36ST/A) and no sexual chromosome differentiation. C-banding showed centromeric staining in all chromosomes. The first chromosome pair, besides centromeric coloration, presented a totally heterochromatic long arm. The nucleolus organizer regions (NORs) were studied by means of AgNO3. NORs were located at the short arm of the second chromosome pair.

Este estudo descreve o cariótipo de Geophagus cf. proximus. Espécimes foram coletados no lago Água Preta, Parque Ambiental de Belém, Estado do Pará, Brasil. O cariótipo obtido apresentou 2n = 48 cromossomos (NF = 60: 12M/SM+36ST/A), sem diferenciação de cromossomos sexuais. O bandeamento C mostrou marcações centroméricas em todos os cromossomos. O primeiro par cromossômico, além da coloração centromérica, apresentou o braço longo totalmente heterocromático. As regiões organizadoras do nucléolo (RONs) foram estudadas por meio da coloração de AgNO3. As RONs foram encontradas no braço curto do segundo par de cromossomos.

Austrodiplostomum compactum (Lutz, 1928) (Digenea, Diplostomidae) in the eyes of fishes from Paraná river, Brazil - doi: 10.4025/actascibiolsci.v34i2.9337

Parasitological indexes of Austrodiplostomum compactum (Digenea, Diplostomidae) in fishes from the Paraná River, Presidente Epitácio region, state of São Paulo, Brazil, and their relationship with climate and water quality are evaluated. Fifty-one specimens of Plagioscion squamosissimus, 39 Geophagus surinamensis, 27 Hoplias malabaricus and 23 Cichla sp. were collected between June 2007 and June 2008. Water quality and rainfall indexes were measured monthly. P. squamosissimus had the highest parasite rate, with 98% total prevalence, intensity of infection varying between 1 and 255 and parasite mean abundance totaling 40.5 ± 9.9. H. malabaricus had the next parasite rate, with 66.6% total prevalence, parasite intensity between 2 and 184 and mean abundance totaling 22.4 ± 20.9. Cichla sp. had a total prevalence of 52.1%, intensity between 1 and 21, and mean abundance 4.3 ± 2.9. Finally, G. surinamensis had a total prevalence of 46.1%, intensity between 1 and 53 and mean abundance 7.1 ± 8.8. A survey of diplostomid infection in Brazil and the role of piscivore fish as an important host have also been discussed.

Diplostomidae metacercariae (Digenea: Diplostomoidea) in Geophagus brasiliensis (Perciformes: Cichlidae) from Guandu river, State of Rio de Janeiro, Brazil - doi: 10.4025/actascibiolsci.v34i2.5957 / Metacercárias de Diplostomidae (Digenea: Diplostomoidea) em Geophagus brasiliensis (Perciformes: Cichlidae) do rio Guandu, Estado do Rio de Janeiro, Brasil - doi: 10.4025/actascibiolsci.v34i2.5957

The qualitative and quantitative analyses of diplostomid metacercariae in Geophagus brasiliensis (Quoy & Gaimard, 1824) of the Guandu river, Seropédica, Rio de Janeiro, Brazil, are provided. Between April 2006 and March 2007, 200 specimens of G. brasiliensis were collected and necropsied. Further, five morphotypes of diplostomid metacercariae were obtained, namely, Austrodiplostomum compactum, Diplostomum sp., Posthodiplostomum sp. 1, Posthodiplostomum sp. 2 and Neascus type 1. Whereas the metacercariae of Diplostomum sp., Posthodiplostomum sp. 1 and Posthodiplostomum sp. 2 were described, a new site of infection of A. compactum was registered and a new geographical report for Neascus type 1, responsible for the black-spot disease, has been added. Current investigation enhances the importance of G. brasiliensis as an intermediate host of diplostomid trematodes and the diversity of these larvae in the Guandu river.

O presente trabalho teve como objetivo o estudo qualitativo e quantitativo das metacercárias de diplostomídeos em Geophagus brasiliensis (Quoy & Gaimard, 1824) do rio Guandu, Seropédica, Rio de Janeiro, Brasil. Entre abril de 2006 e março de 2007, foram coletados e necropsiados 200 espécimes de G. brasiliensis, sendo obtidos cinco morfotipos de metacercárias de diplostomídeos: Austrodiplostomum compactum, Diplostomum sp.,  Posthodiplostomum sp. 1, Posthodiplostomum sp. 2 e Neascus tipo 1. No presente trabalho, foram descritas as metacercárias de Diplostomum sp., Posthodiplostomum sp. 1 e  Posthodiplostomum sp. 2, além de registrar novo sítio de infecção de A. compactum e aumentar o conhecimento da distribuição geográfica de Neascus tipo 1, causadora da doença dos pontos pretos. O presente trabalho aponta para a importância de G. brasiliensis como hospedeiro intermediário de trematódeos diplostomídeos e sobre a diversidade dessas larvas no rio Guandu.

Austrodiplostomum compactum (Lutz, 1928) (Digenea, Diplostomidae) in the eyes of fishes from Paraná river, Brazil / Austrodiplostomum compactum (Lutz, 1928) (Digenea, Diplostomidae) em olhos de peixes do rio Paraná, Brasil

Parasitological indexes of Austrodiplostomum compactum (Digenea, Diplostomidae) in fishes from the Paraná River, Presidente Epitácio region, state of São Paulo, Brazil, and their relationship with climate and water quality are evaluated. Fifty-one specimens of Plagioscion squamosissimus, 39 Geophagus surinamensis, 27 Hoplias malabaricus and 23 Cichla sp. were collected between June 2007 and June 2008. Water quality and rainfall indexes were measured monthly. P. squamosissimus had the highest parasite rate, with 98% total prevalence, intensity of infection varying between 1 and 255 and parasite mean abundance totaling 40.5 ± 9.9. H. malabaricus had the next parasite rate, with 66.6% total prevalence, parasite intensity between 2 and 184 and mean abundance totaling 22.4 ± 20.9. Cichla sp. had a total prevalence of 52.1%, intensity between 1 and 21, and mean abundance 4.3 ± 2.9. Finally, G. surinamensis had a total prevalence of 46.1%, intensity between 1 and 53 and mean abundance 7.1 ±8.8. A survey of diplostomid infection in Brazil and the role of piscivore fish as an important host have also been discussed.

Este estudo avaliou os índices parasitológicos de Austrodiplostomum compactum (Digenea, Diplostomidae) em peixes do rio Paraná, região de Presidente Epitácio, Estado de São Paulo, Brasil e sua relação com o clima e qualidade da água. Cinquenta e um espécimes de Plagioscion squamosissimus, 39 Geophagus surinamensis, 27 Hoplias malabaricus e 23 Cichla sp. foram coletados de junho de 2007 a junho de 2008. Qualidade da água e pluviosidade foram medidas mensalmente. O peixe mais parasitado foi P. squamosissimus com 98% de prevalência total, intensidade de infecção variando de 1 a 255 e abundância média de 40,5 ± 9,9. O segundo peixe mais parasitado foi H. malabaricus com 66,6% de prevalência total, intensidade de 2 a 184 e abundância média de 22,4 ± 20,9. Cichla sp. apresentou 52,1% de prevalência, intensidade de 1 a 21 e abundância média de 4,3 ± 2,9. Finalmente, G. surinamensis apresentou 46,1% de prevalência, intensidade de 1 a 53 e abundância média de 7,1 ± 8,8. Um levantamento de infecções por diplostomídeos no Brasil e o papel de peixes piscívoros como importantes hospedeiros é também discutido.

Metacercárias de Diplostomidae (Digenea: Diplostomoidea) em Geophagus brasiliensis (Perciformes: Cichlidae) do rio Guandu, Estado do Rio de Janeiro, Brasil / Diplostomidae metacercariae (Digenea: Diplostomoidea) in Geophagus brasiliensis (Perciformes: Cichlidae) from Guandu river, State of Rio de Janeiro, Brazil

O presente trabalho teve como objetivo o estudo qualitativo e quantitativo das metacercárias de diplostomídeos em Geophagus brasiliensis (Quoy & Gaimard, 1824) do rio Guandu, Seropédica, Rio de Janeiro, Brasil. Entre abril de 2006 e março de 2007, foram coletados e necropsiados 200 espécimes de G. brasiliensis, sendo obtidos cinco morfotipos de metacercárias de diplostomídeos: Austrodiplostomum compactum, Diplostomum sp., Posthodiplostomum sp. 1, Posthodiplostomum sp. 2 e Neascus tipo 1. No presente trabalho, foram descritas as metacercárias de Diplostomum sp., Posthodiplostomum sp. 1 e Posthodiplostomum sp. 2, além de registrar novo sítio de infecção de A. compactum e aumentar o conhecimento da distribuição geográfica de Neascus tipo 1, causadora da doença dos pontos pretos. O presente trabalho aponta para a importância de G. brasiliensis como hospedeiro intermediário de trematódeos diplostomídeos e sobre a diversidade dessas larvas no rio Guandu.

The qualitative and quantitative analyses of diplostomid metacercariae in Geophagus brasiliensis (Quoy & Gaimard, 1824) of the Guandu river, Seropédica, Rio de Janeiro, Brazil, are provided. Between April 2006 and March 2007, 200 specimens of G. brasiliensis were collected and necropsied. Further, five morphotypes of diplostomid metacercariae were obtained, namely, Austrodiplostomum compactum, Diplostomum sp., Posthodiplostomum sp. 1, Posthodiplostomum sp. 2 and Neascus type 1. Whereas the metacercariae of Diplostomum sp., Posthodiplostomum sp. 1 and Posthodiplostomum sp. 2 were described, a new site of infection of A. compactum was registered and a new geographical report for Neascus type 1, responsible for the black-spot disease, has been added. Current investigation enhances the importance of G. brasiliensis as an intermediate host of diplostomid trematodes and the diversity of these larvae in the Guandu river.

Variação sazonal dos metazoários parasitos de Geophagus brasiliensis( Perciformes: Cichlidae ) no rio Guandu, Estado do Rio de Janeiro,Brasil / Seasonal variation of metazoan parasites of Geophagus brasiliensis (Perciformes: Cichlidae ) from the Guandu river, State of Rio de Janeiro, Brazil

O presente trabalho estuda a variação sazonal dos metazoários parasitos deGeophagus brasiliensis do rio Guandu, Estado do Rio de Janeiro, Brasil. Para isso foramrealizadas quatro coletas trimestrais de 50 espécimes de G. brasiliensis entre abril de 2006 emarço de 2007, nas diferentes estações do ano. Foram coletadas 14 espécies de metazoáriosparasitos: seis digenéticos (Crassicutis sp. em estágio adulto, e cinco tipos de metacercárias,Austrodiplostomum compactum, Diplostomulum sp., Neascus tipo 1, Neascus tipo 2 ePosthodiplostomum sp.); três nematóides (larvas de Contracaecum sp., adultos de Cucullanus sp.e Procamallanus (Procamallanus) peraccuratus); o monogenético (Sciadicleithrum guanduensis); oacantocéfalo (Neoechinorhynchus paraguayensis); larvas gloquídias de molusco e espécies dehirudíneos das famílias Glossiphonidae e Piscicolidae. Com exceção dos hirudíneosglossifonídeos, todas as espécies apresentaram picos de prevalência e abundânciaprincipalmente naqueles peixes coletados na primavera, o que pode indicar umasazonalidade dessas espécies de parasitos em G. brasiliensis do rio Guandu.

The present work studied the seasonal variation of the metazoan parasites of Geophagusbrasiliensis from the Guandu river, State of Rio de Janeiro, Brazil. Four collections of 50specimens of G. brasiliensis were accomplished between April 2006 and March 2007, in thedifferent seasons. A total of 14 species of metazoan parasites were obtained: six trematodes(Crassicutis sp. in adult stage and five metacercariae, Austrodiplostomum compactum,Diplostomulum sp., Neascus type 1, Neascus type 2 and Posthodiplostomum sp.), three nematodes(Contracaecum sp. larval, Cucullanus sp. and Procamallanus (Procamallanus) peraccuratus adult);monogenean (Sciadicleithrum guanduensis); acanthocephalan (Neoechinorhynchus paraguayensis),larval glochidia; and hirudinean species of Glossiphonidae and Piscicolidae. With theexception of Glossiphonidae hirudinean, all parasite species showed prevalence andabundance peaks mainly in the spring sample, which could indicate seasonality of theseparasite species in G. brasiliensis from the Guandu River.

Neascus-type metacercariae in Geophagus brasiliensis (Perciformes: Cichlidae) of Peixe river, Juiz de Fora, Brazil - DOI: 10.4025/actascibiolsci.v30i3.493 / Metacercárias de Neascus sp. em Geophagus brasiliensis (Perciformes: Cichlidae) do rio do Peixe, Juiz de Fora, Brasil - DOI: 10.4025/actascibiolsci.v30i3.493

Neascus-type metacercariae, which cause the black spot disease, are described in specimens collected from 33 samples of Geophagus brasiliensis from the Peixe river, in Monte Verde, Juiz de Fora, state of Minas Gerais, Brazil, during March and May 2006. The main morphological features of these metacercariae are: genital primordia composed of three cell masses located in the hind body, and a median dorsal vessel of the reserve bladder around the acetabulum. Thirty fish specimens (90.9%) were parasitized by metacercariae, with mean infection intensity of 15.6 ± 16.1 (1-75). Also, a positive correlation was detected between G. brasiliensis total length and the parasite abundance (r = 0.459; p 0.01).

A metacercária de Neascus sp., causadora da doença dos pontos pretos, é descrita em espécimes de Geophagus brasiliensis coletados no Brasil. Entre março e maio de 2006, foram capturados 33 espécimes de G. brasiliensis, coletados com o auxílio de vara e anzol no Rio do Peixe, Monte Verde, município de Juiz de Fora, Estado de Minas Gerias. Dos 33 espécimes examinados, 30 (90,9%) apresentaram-se parasitados por metacercárias causadoras dos pontos pretos, com intensidade média de infecção de 15,6 ± 16,1 (1 75). Foi observada correlação significativa entre o comprimento total de G. brasiliensis e a abundância parasitária (r = 0,459; P 0,01). As principais características morfológicas desta metacercária foram: primórdio genital representado por três massas celulares, localizadas posteriormente na parte posterior do corpo e vaso mediano dorsal da bexiga de reserva se estendendo entorno do acetábulo.

Ecology of the community of metazoan parasites of acará Geophagus brasiliensis (Quoy e Gaimard, 1824) (Perciformes: Cichlidae) from Guandu river, State of Rio de Janeiro, Brazil - DOI: 10.4025/actascibiolsci.406 / Ecologia da comunidade de metazoários parasitos do acará Geophagus brasiliensis (Quoy e Gaimard, 1824) (Perciformes: Cichlidae) do rio Guandu, Estado do Rio de Janeiro, Brasil - DOI: 10.4025/actascibiolsci.v28i4.406

Fifty specimens of acarGeophagus brasiliensis (Quoy and Gaimard, 1824) from Guandu River, (224832S, 433735W), Rio de Janeiro State, Brazil were studied for their metazoan parasites during December 2004 and November 2005. A total of nine species of metazoan parasites were collected. Posthodiplostomum macrocotyle Dubois, 1937 (metacercariae) found in the eyes, was the most prevalent species (88%) with the highest mean intensity value (12.4), followed by the metacercariae of Austrodiplostomum compactum (Lutz, 1928) and the hirudinean Glossiphoniidae gen. sp. showing prevalence of 14% and 10%, respectively. No parasite species showed significant correlation between the total body length of the host and their prevalence. Posthodiplostomum macrocotyle showed significant correlation between the total body length of the host and their abundance. The sex of the hosts influenced the abundance of P. macrocotyle, A. compactum and Glossiphoniidae gen. sp. being the females the most parasited. The parasite species richness showed a mean value of 1.240.69 (0-3). The parasite species showed an aggregated distribution pattern.

Foram estudados 50 acarás Geophagus brasiliensis (Quoy e Gaimard, 1824) provenientes do rio Guandu, coletados próximo barragem da Estação de Tratamento de àgua (ETA) (22º4832S, 43º3735O), no Estado do Rio de Janeiro, no período de dezembro de 2004 novembro de 2005. Nove espécies de metazoários parasitos foram coletadas. O digenético Posthodiplostomum macrocotyle Dubois, 1937 (metacercária) foi a espécie mais prevalente (88%) e com a maior intensidade média (12,4), sendo a maioria dos espécimes encontrados parasitando os olhos, seguida pela metacercária Austrodiplostomum compactum (Lutz, 1928) e pelo hirudíneo Glossiphoniidae gen. sp., que apresentaram prevalências de 14% e 10%, respectivamente. Nenhum parasito apresentou correlação significativa entre o comprimento total do corpo do hospedeiro e sua prevalência. Posthodiplostomum macrocotyle apresentou correlação significativa entre o comprimento total do corpo do hospedeiro e sua abundância. O sexo dos hospedeiros influenciou a abundância de P. macrocotyle, A. compactum e Glossiphoniidae gen. sp., sendo as fêmeas as mais parasitadas. A riqueza parasitária apresentou uma média de 1,24±0,69 (0-3). Os parasitos apresentaram um padrão de distribuição agregado.

Avaliação de locos ssr (single sequence repeats) desenvolvidos para oreochromis niloticus e tropheus moorii em alguns ciclidios neotropicais / Avaliation of SSR (single sequence repeats) locus developed from Oreochromis niloticus and Tropheus morrii in some neotropical ciclhids

ôPrimersö de locos SSR (Single Sequence Repeats) desenvolvidos a partir de tilápia (Oreochromis niloticus) (UNH104, UNH108 e UNH160) e de Tropheus moorii (TmoM27) foram testados em alguns ciclídios brasileiros. Destes microssatélites avaliados, somente o TmoM27 apresentou amplificação para os gêneros Geophagus e Crenicichla (Cichlidae). Esse loco foi monomórfico em Crenicichla iguassuensis e nos morfotipos Crenicichla sp1 e sp2, com um tamanho estimado da ordem de 346 pb. Pelo menos nesse segmento de DNA não há diferenciação entre C. iguassuensis e as supostas sp1 e sp2. A espécie Geophagus brasiliensis apresentou, contudo, dois alelos com tamanhos de 346 e 358 pb. O menor alelo de G. brasiliensis correspondia ao alelo encontrado nas populações de Crenicichla, contudo sua identidade de bases não foi estabelecida. Observou-se equilíbrio de Hardy-Weinberg para o loco TmoM27, tanto em G. brasiliensis como em Oreochromis niloticus. O loco TmoM27 apresentou o mesmo nível de polimorfismo obtido por outros pesquisadores que analisaram este microssatélite nas espécies de Crenicichla saxatilis e Oreochromis niloticus. O locus TmoM27 pode ser usado para análise da heterozigosidade em Geophagus brasiliensis. Os locos UNH 104, UNH108 e UNH160 não tem aplicação em estudos de estrutura de populações para Crenicichla e Geophagus, pois nenhum produto de amplificação foi obtido nestas espécies.

PLASTICITY OF JAW AND SKULL MORPHOLOGY IN THE NEOTROPICAL CICHLIDS GEOPHAGUS BRASILIENSIS AND G. STEINDACHNERI.

I examined plasticity of jaw and skull morphology induced by feeding different diets in two species of the neotropical cichlid genus Geophagus. The two species possess different modes of development, which affect the size at which young begin feeding. I hypothesized that the difference in size at first feeding could lead to a difference in the amount of change inducible in the two species. The young of the substrate-spawning species, G. brasiliensis, which begin feeding at a smaller size, were predicted to be more plastic than those of the mouthbrooding species, G. steindachneri. The two diets used to induce differences were brine shrimp nauplii and chironomid larvae. Numerous measures of the jaw and skull differed significantly between groups fed the two diets but the amount of plasticity induced was small and would not present a problem for taxonomists. Contrary to my prediction, both the magnitude and pattern of plasticity induced in the two species was similar. Thus, mode of parental care and the size at which young begin feeding do not affect the degree of plasticity. Fish fed brine shrimp nauplii were longer in oral jaw region, but were shorter and shallower in the area behind the oral jaws. An additional group of G. brasiliensis was fed flake food to compare the results of this study to other studies. The differences in measures between fish fed brine shrimp diets and flake food diets were greater than those between fish fed brine shrimp and chironomid larvae. A possible role of plasticity for enhancing rather than retarding morphological evolution is discussed.