SODIUM FLUORIDE DISTRESSES CHROMATOPHORE INTEGRITY AND BEHAVIOUR OF GUPPY, POECILIA RETICULATA PETERS

The present study was undertaken to investigate the toxicological effect of ?uoride (as NaF) on chromatophores in skin of larvivorous fish, Poecilia reticulata Peters after chronic exposure. Guppy is supposed to be amongst the most colourpolymorphic vertebrates in the animal kingdom. Fish were exposed to three sub-lethal concentrations of Sodium fluoride viz. lowest (5.75 ppm), lower intermediate (7.18 ppm) and higher intermediate (9.58 ppm), which were selected on the basis of 96 hrs. LC value of 115 ppm. 50 Anomalous behavioral alterations observed in NaF intoxicated fish were restlessness, erratic swimming movement, periodic surface to bottom movement, recurrent surfacing activity, loss of equilibrium, amplified gulping and increased opercular activity were pragmatically seen. Significant variation in colouration was observed in all the experimental groups as compared to control. The melanophores showed notable pigment aggregation state and/or pigment dispersion state. Structurally, melanophores were distinguished into three types viz., reticulate, stellate and punctuate. The severity in distortion of structure and number of chromatophore increased with increasing concentrations of fluoride. Several distortions in morphology and even functional integrity of chromatophores when compared with the control group were observed, for instance, rupture of pigment cells accompanied by breakage in dendritic processes, conversion of one type of chromatophore into another type, augmentation and detachment between adjacent chromatophores, variation in number with complete loss of cellular activity. The derangement in structural integrity was observed to be dose dependent and increased with increasing concentrations of Sodium fluoride, thus making the fish unfit for survival. The attractive pigmentation of the male Guppy fish was abridged making them less attractive for their mate thus affecting reproductive potential of the fish.

Norethindrone-induced masculinization and progeny testing in guppy, Poecilia reticulata (Peters 1859).

Norethindrone(NE) was evaluated for its efficacy on alteration of sex ratio of P. reticulata. Either the young fry or the brooders and the resultant fry were fed a commercial diet incorporated with NE at 0, 25, 50, 75 and 100 mg kg-1 diet (ppm) for 30-40 d in rectangular glass aquaria; this was followed by 40-60 d rearing on NE-free diet in out-door concrete tanks. In general, the androgen treatment altered sex ratio, leading to the production of a dose dependent increase in the percentage of males. The oral administration of the steroid at 75 ppm for 40 d or 100 ppmfor 30 or 40 d to first feeding fry, yielded 100% males. On the other hand, NE administration to brooders before parturition and the resultant fry also produced an all-male population of guppy. The sex ratio of the untreated control was almost 1:1. The survival of fish in all the trials was high, ranging between 67 and 100%. Mating masculinized males (“XX” male) with normal female resulted in an all-female progeny, while crossing normal male (XY) from treatment groups with normal female sired normal sex ratio (1:1), elucidating XX-XY sex determination system in the guppy.

In vitro evaluation of adhesion and aggregation abilities of four potential probiotic strains isolated from guppy (Poecilia reticulata)

The aim of this work was to study the probiotic-related characteristics of four strains of bacteria isolated from the normal flora of the guppy, Poecilia reticulata. In vitro results showed that the strains, namely, MBTU_PB1, MBTU_PB2, MBTU_PB3 and MBTU_PB4 had higher adhesion abilities than the tested indicator strains. However, an association between the cell-surface hydrophobicity and the ability to adhere to the intestinal mucus was not observed for these strains. Further, the selected strains were strongly autoaggregating (autoaggregation percentage ≥ 80) and also showed strain-specific coaggregation abilities with the tested indicator strains.

Pseudobrânquia do guaru Poecilia reticulata (Peter, 1859): análise estrutural, morfométrica e histoquímica para detecção de glicoconjugados / Pseudo-gill of guppy, Poecilia reticulata (Peter, 1859): structural, morphometric, and histochemical analyses for the detection of glycoconjugates

A morfologia, os parâmetros citomorfométricos e os glicoconjugados presentes na pseudobrânquia de guaru, Poecilia reticulata Peter, 1859 (Cyprinodontiformes: Poeciliidae), foram investigados por microscopia de luz acoplada ao sistema de captura e análise de imagens, juntamente por histoquímica com lectinas. A anatomia microscópica indicou que P. reticulata possui pseudobrânquia glandular formada por dois lóbulos, a qual se localiza abaixo do epitélio faringiano. O órgão é constituído por parênquima vascularizado e rico em células pseudobranquiais. Esse tipo celular exibe estado citofisiológico ativo, com abundante sistema de biomembranas e ausência de óstio na superfície apical,que por sua vez é encontrado nas células ricas em mitocôndrias das holobrânquias. Assim, indica-se que as células da pseudobrânquia se distinguem das células das holobrânquias em relação à morfologia, histoquímica e fisiologia. Em decorrência dessas características intrínsecas, a pseudobrânquia de alevinos do guaru pode desempenhar funções não respiratórias nas fases iniciais do desenvolvimento. Além disso, a caracterização da pseudobrânquia do guaru possibilitará estudos futuros sobre o efeito de poluentes aquáticos em espécies biomonitoras, como P. reticulata.

The morphology, cytomorphometric parameters, and glycoconjugates present in the pseudo-gill of guppy, Poecilia reticulata Peter, 1859 (Cyprinodontiformes: Poeciliidae), were investigated by light microscopy coupled to image capture and analysis system, and also by lectin histochemistry. The microscopic anatomy indicates that P. reticulata has a glandular pseudo-gill formed by two lobes, located underneath the pharynx epithelium. The organ is formed by vascularized parenchyma rich in pseudo-gill cells. This cell type exhibits active cytophysiological state with an abundant system of biomembranes and lacking of ostium in apical surface, which in turn is found in the mitochondria-rich cells of the holobranch. This indicates that the pseudo-gill cells distinguishe from the holobranch cells in their morphology, histochemistry and physiology. Due to these intrinsic characteristics, the pseudo-gill of guppy fingerlings may have non-respiratory function in the initial phase of their development. The characterization of guppy's pseudo-gill could facilitate further studies about the effect of water pollutants on biomonitor species, such as P. reticulata.

Length-weight relationship and reproduction of the guppy Poecilia reticulata (Cyprinodontiformes: Poeciliidae) in urban drainage channels in the Brazilian city of Belém / Relação peso-comprimento e reprodução do guppy Poecilia reticulata (Cyprinodontiformes: Poeciliidae) em canais de coleta residual na região metropolitana de Belém, Pará, Brasil

This paper describes the length-weight relationship, size at first maturation (L), and breeding season of Poecilia reticulata found in drainage channels on the campus of the Federal University of Pará (UFPA) in the Brazilian city of Belém. A total of 1.936 specimens (942 males and 994 females) were collected in monthly samples of the study area between June, 2006, and March, 2007. Females were significantly longer and heavier than males. The length-weight relationship for males was established by the equation Pt = 5 × 10-5 × Ct2.397 and for females by Pt = 3 × 10-6 × Ct3.419. The estimated value of L was 17.5 mm for males and 20.4 mm for females, suggesting that males initiate reproductive activity at a smaller size than females. The abundance of mature females did not vary significantly among months, and there was little variation in the sex ratio, which was close to parity overall. Despite the adverse conditions encountered in the UFPA drainage system, P. reticulata appeared to have adapted its biological processes adequately.

O presente trabalho tem por objetivo descrever aspectos populacionais relacionados ao estabelecimento da relação peso/comprimento, estimativa de tamanho de primeira maturação (L) e período reprodutivo de Poecilia reticulata encontrados em sistemas de coleta residual no campus da Universidade Federal do Pará, região metropolitana de Belém - PA (Brasil). Foram realizadas coletas mensais no período de junho de 2006 a março de 2007, utilizando um puçá, que resultou na captura de 1.936 exemplares, sendo 942 machos e 994 fêmeas. As fêmeas apresentaram-se maiores e mais pesadas que os machos. A relação peso/comprimento para machos foi estabelecida pela equação Pt = 5 × 10-5 × Ct2,397 e para fêmeas esta foi dada pela fórmula Pt = 3 × 10-6 × Ct3,419. Os valores estimados para L foi 17,5 mm para machos 20,4 mm para fêmeas, sugerindo que os machos iniciam atividades reprodutivas em tamanhos menores que as fêmeas. A frequência mensal de fêmeas maduras não variou significativamente. Além disso, também não foram encontradas diferenças na proporção sexual durante os períodos investigados, sendo no geral, a proporção de fêmeas iguais as de machos. Desta forma, verificamos que, apesar das condições presentes nos sistemas de coleta residual da UFPA, a espécie P. reticulata parece ter adaptado seus processos biológicos.

Metacestodes of Glossocercus auritus (Cyclophyllidea, Gryporhynchidae) in Poecilia reticulata (Pisces, Poeciliidae) from Brazil / Metacestoides de Glossocercus auritus (Cyclophyllidea, Gryporhynchidae) em Poecilia reticulata (Pisces, Poeciliidae) no Brasil

Studies on fish parasites in Pampulha dam, Belo Horizonte, Minas Gerais, Brazil, found specimens of Poecilia reticulata Peters, 1859 harboring natural infection by larval stages of tapeworms. A total of 250 specimens of P. reticulata were collected and analyzed between February and August 2010, of which 23 were found infected (prevalence 9.2 percent) with one metacestode each (mean intensity 1, mean abundance 0.09). The analyses of the parasites, particularly the morphology of rostellar hooks, made it possible to identify Glossocercus auritus (Rudolphi, 1818). This is the first report of G. auritus metacestode in South America and P. reticulata is a newly known host for this parasite.

Em estudo da helmintofauna de peixes oriundos da represa da Pampulha, Belo Horizonte, Minas Gerais, Brasil, exemplares de Poecilia reticulata Peters, 1859 foram encontrados naturalmente infectados por larvas de cestóides. De 250 espécimes de P. reticulata coletados e analisados entre fevereiro e agosto de 2010, 23 (prevalência de infecção 9,2 por cento) apresentavam-se infectados por um metacestóides cada (intensidade média 1, abundância média 0,09). A análise dos parasitos, em especial a morfologia dos acúleos rostelares, permitiram a identificação de Glossocercus auritus (Rudolphi, 1818). Este é o primeiro registro de metacestóide de G. auritus para a América do Sul, sendo P. reticulata um novo hospedeiro conhecido para o parasito.

Eficacia del control de larvas de mosquitos (Diptera: Culicidae) con peces larvívoros / Effectiveness of the mosquito larvae control (Diptera: Cullicidae) by larvivorous fish

OBJETIVO: se realizó un estudio de cohorte en los Consejos Populares de Báez y Guaracabulla, pertenecientes al municipio Placetas, provincia Villa Clara, para determinar la eficacia de 3 especies de peces fluviales: Gambusia punctata Poey, 1854, Gambusia puncticulata Poey, 1854 y Poecilia reticulata Peter, 1895, en el control de larvas de mosquitos en depósitos utilizados por la población para almacenar agua. MÉTODOS: la investigación se inició en el mes de abril de 2006 y culminó en mayo de 2007, se seleccionaron solo los tanques bajos (interior y exterior de las viviendas) por ser más factibles de evaluar, se trabajó con una muestra de 1 740 depósitos que se dividieron en 2 grupos, los cuales se evaluaron por espacio de 1 año. RESULTADOS: el riesgo de encontrar focos de mosquitos fue superior en el grupo de depósitos que no estaban expuestos a la presencia de peces, la diferencia de riesgo permitió plantear que por cada 100 depósitos tratados con peces, se logró evitar 8 focos de mosquitos. CONCLUSIONES: los peces larvívoros constituyen una excelente alternativa contra las poblaciones larvales de culícidos en depósitos utilizados por la población para almacenar agua, que resulta un factor de protección ante la incidencia de focos de mosquitos.

OBJECTIVE: a cohort study was conducted in People´s councils in Báez and Guaracabulla located in Placetas municipality, Villa Clara province, for the purpose of determining the effectiveness of three river fish called Gambusia punctata Poey, 1854, Gambusia puncticulata Poey, 1854 y Poecilia reticulata Peter, 1895 in the control of mosquito larvae inside water reservoirs used by the population. METHODS: the study began in April 2006 and ended May, 2007; the selected water tanks were placed inside and outside the houses) since they were more easy to be evaluated. The sample covered 1 740 tanks divided into 2 groups and evaluated for one year. RESULTS: the risk of finding mosquito foci was higher in the group of reservoirs non-exposed to the action of fish; this difference allowed stating that 8 mosquito foci were prevented per every 100 reservoirs treated with fish. CONCLUSIONS: larvivorous fish are an excellent choice to treat Cullicidae larval populations existing in water tanks and also a protective factor against incidence of mosquito foci.

Efecto anabólico y androgénico del esteroide acetato de trembolona en el guppy (Poecilia reticulata) / Anabolic and androgenic effect of steroid trenbolone acetate on guppy (Poecilia reticulata)

The effect of semi-synthetic steroid trenbolone acetate (TBA) on the ornamental fish Poecilia reticulata (guppy) was studied. The steroid at a dose of 300 mg/kg feed was administered to 30 days old juvenile specimens during 60 days. Forty days after treatment was ended, an evaluation aimed to determine the steroid residual effect was undertaken. Survival, masculinization ratio and the drug anabolic effect were analyzed. Results showed TBA to be effective to induce masculinization, differing (P < 0.001) with the control group, which registered 32% males and 68% females. TBA turned out to be an excellent anabolic as well, since treated fish showed weight increase, a larger body and an increased size of caudal fin. The steroid did not cause any damage on the treated population. The survival factor was 93.3% for the treated fish as compared to 83% for the control group.

Se investigó el efecto del esteroide semisintético acetato de trembolona (ATB) en el pez de ornato Poecilia reticulata (guppy). Especímenes juveniles de 30 días de edad fueron tratados con el esteroide a dosis de 300 mg/kg de alimento durante 60 días. Al término del tratamiento, 40 días después, se estimó el efecto residual del esteroide. Se analizó la sobrevivencia, la proporción de peces masculinizados, así como el efecto anabólico. Los resultados indicaron que el ATB es eficaz para inducir la masculinización, a diferencia del grupo testigo, donde se registraron 32% de machos. Asimismo, el ATB tuvo un efecto anabólico, ya que los peces tratados mostraron mayor peso y talla e incremento de la aleta caudal. El esteroide no causó daño en la población tratada, al sobrevivir 93.3% de los peces, comparado con 83% del grupo testigo.

Analyses of the sediment toxicity of Monjolinho River, São Carlos, São Paulo State, Brazil, using survey, growth and gill morphology of two fish species (Danio rerio and Poecilia reticulata)

The objective of this work was to evaluate the toxicity of the sediments of the Monjolinho River (São Carlos - São Paulo/Brazil), through partial chronic toxicity bioassays with juveniles of D. rerio and P. reticulata. Histological analyses of the gills and biometric measurements were conducted to detect the possible deleterious effects that caused the death. In all points the sampled the alterations were found in the gills (hyperplasia, fusion of secondary lamellas and dilation of blood vessels), with the most intense lesions (second stage) occurring at the point two. The biometric analysis pointed to inadequate conditions for the growth of the test-organisms when exposed to the sediment samples. These results showed that the conditions of these environments were not suitable for the survival and growth of these fishes.

Este trabalho teve como objetivo avaliar a toxicidade dos sedimentos do rio Monjolinho (São Carlos - São Paulo/Brasil), por meio de bioensaios de toxicidade crônicos parciais com juvenis de D. rerio e P. reticulata. Foram realizadas análises histológicas das brânquias dos organismos para detectar possíveis efeitos deletérios que antecedam a mortalidade. Em todos os pontos amostrados, foram verificadas alterações nas brânquias (hiperplasia, fusão de lamelas secundárias e dilatação de vasos sanguíneos), sendo no ponto dois foram encontradas lesões mais acentuadas (segundo estágio). A análise biométrica dos indivíduos expostos em amostras de sedimento demonstrou condições inadequadas para o crescimento e desenvolvimentos dos organismos-teste em todo o ambiente estudado. Os sedimentos apresentaram maior toxicidade no período chuvoso, sendo estes resultados confirmados por meio das análises histológicas das brânquias dos organismos expostos, as quais demonstraram lesões mais acentuadas no mesmo período. Tal situação possivelmente decorre dos impactos antrópicos os quais o sistema está suscetível (efluentes domésticos, industriais e agrícolas), que foram constatados pelas análises físicas e químicas dos sedimentos.