Structure and dynamics of the protoplankton community in an environmentally protected urban stream / Estrutura e dinâmica da comunidade de protoplâncton em um córrego urbano ambientalmente protegido

We aimed to investigate spatial and temporal scales, abundance, and factors that structure the communities of protozoans in a tropical urban stream. Methods: Samples of water for analysis of biological communities (testate amoebae, ciliates and bacteria) and limnological variables were taken in the Mandacaru stream located in the Conservation Unit of Parque do Cinquentenário, in the city of Maringá, Paraná State, Brazil, in two hydrological periods (dry and rainy). We calculated the Water Quality Index (WQI) composed by nine parameters of water quality (dissolved oxygen, thermotolerant coliforms, pH, BOD, water temperature, total nitrogen, total phosphorous, turbidity, and total solids), Trophic State Index (TSI) for phosphorous and we used a Redundancy Analysis (RDA) to verify the influence of environmental variables in the protozoan community. Results: The WQI showed that water quality was considered good in some points and considered bad in other points. The TSI for phosphorus classified the stream as mesotrophic in the majority of sampled sites points (mean between 53.09 and 58.35). We identified 19 taxa of testate amoebae, belonging to six families, being Difflugiidae, Centropyxidae, and Arcellidae those with more species and 71 infrageneric taxa of ciliates, distributed in 12 orders being Peniculida the most representative order, followed by Euplotida. According to RDA analysis, samples of the dry period were characterized by higher values of bacteria density and concentrations of chlorophyll-a, total phosphorous, and total nitrogen. Ciliates and testate amoebae presented higher abundance values in some of the months characterized by higher precipitation and in conditions of higher system productivity. Conclusion: we may conclude that the Mandacaru stream, although strongly influenced by anthropic action, still presents an acceptable water quality. Lastly, we emphasize that protists abundance was strongly influenced by system productivity. This was evidenced by elevated protozoan densities where there was higher primary and bacterial productivity. Thus, these organisms must be considered in studies that aim at the identification of organisms that may indicate anthropic impacts and environmental quality.(AU)

O objetivo foi investigar, em escalas espacial e temporal, a abundância das comunidades de protozoários bem como os fatores intervenientes na estruturação das mesmas em um córrego urbano. Métodos: Amostras de água para análise de comunidades biológicas (amebas testáceas, ciliados e bactérias) e para análise de variáveis limnológicas foram tomadas no córrego Mandacaru localizado na Unidade de Conservação do Parque do Cinquentenário, na cidade de Maringá, Paraná State, Brasil, em dois períodos hidrológicos (seco e chuvoso). Calculamos o Índice de Qualidade de Água (IQA), o Índice de Estado Trófico (ETI) para fósforo e utilizamos uma Análise de Redundância (RDA) para verificar a influência de variáveis ambientais na comunidade de protozoários. Resultados: O IQA mostrou que a qualidade da água foi considerada boa em alguns pontos e considerada ruim em outros pontos, e o ETI para o fósforo classificou o córrego como mesotrófico na maioria dos locais amostrados (média entre 53,09 e 58,35). Foram identificados 19 táxons de amebas testáceas, pertencentes a seis famílias, sendo Difflugiidae, Centropyxidae e Arcellidae as mais especiosas, e 71 táxons de ciliados, distribuídos em 12 ordens, sendo Peniculida a ordem mais representativa, seguida por Euplotida. De acordo com a análise RDA, amostras do período seco foram caracterizadas por maiores valores de densidade bacteriana e concentrações de clorofila-a, fósforo total e nitrogênio total. As amebas testáceas e os ciliados apresentaram valores de abundância maiores em alguns dos meses caracterizados por maior precipitação e em condições de maior produtividade do sistema. Podemos concluir que o córrego Mandacaru, embora fortemente influenciado pela ação antrópica, ainda apresenta uma qualidade de água aceitável. Por fim, enfatizamos que a abundância de protistas foi fortemente influenciada pela produtividade do sistema. Isto foi evidenciado pelas elevadas densidades de protozoários onde houve maior produtividade primária e bacteriana. Assim, esses protistas devem ser considerados em estudos que visem à identificação de organismos que possam indicar impactos antrópicos e qualidade ambiental.(AU)

Structure and dynamics of the protoplankton community in an environmentally protected urban stream

Abstract We aimed to investigate spatial and temporal scales, abundance, and factors that structure the communities of protozoans in a tropical urban stream. Methods: Samples of water for analysis of biological communities (testate amoebae, ciliates and bacteria) and limnological variables were taken in the Mandacaru stream located in the Conservation Unit of Parque do Cinquentenário, in the city of Maringá, Paraná State, Brazil, in two hydrological periods (dry and rainy). We calculated the Water Quality Index (WQI) composed by nine parameters of water quality (dissolved oxygen, thermotolerant coliforms, pH, BOD, water temperature, total nitrogen, total phosphorous, turbidity, and total solids), Trophic State Index (TSI) for phosphorous and we used a Redundancy Analysis (RDA) to verify the influence of environmental variables in the protozoan community. Results: The WQI showed that water quality was considered good in some points and considered bad in other points. The TSI for phosphorus classified the stream as mesotrophic in the majority of sampled sites points (mean between 53.09 and 58.35). We identified 19 taxa of testate amoebae, belonging to six families, being Difflugiidae, Centropyxidae, and Arcellidae those with more species and 71 infrageneric taxa of ciliates, distributed in 12 orders being Peniculida the most representative order, followed by Euplotida. According to RDA analysis, samples of the dry period were characterized by higher values of bacteria density and concentrations of chlorophyll-a, total phosphorous, and total nitrogen. Ciliates and testate amoebae presented higher abundance values in some of the months characterized by higher precipitation and in conditions of higher system productivity. Conclusion: we may conclude that the Mandacaru stream, although strongly influenced by anthropic action, still presents an acceptable water quality. Lastly, we emphasize that protists abundance was strongly influenced by system productivity. This was evidenced by elevated protozoan densities where there was higher primary and bacterial productivity. Thus, these organisms must be considered in studies that aim at the identification of organisms that may indicate anthropic impacts and environmental quality.

Resumo O objetivo foi investigar, em escalas espacial e temporal, a abundância das comunidades de protozoários bem como os fatores intervenientes na estruturação das mesmas em um córrego urbano. Métodos: Amostras de água para análise de comunidades biológicas (amebas testáceas, ciliados e bactérias) e para análise de variáveis limnológicas foram tomadas no córrego Mandacaru localizado na Unidade de Conservação do Parque do Cinquentenário, na cidade de Maringá, Paraná State, Brasil, em dois períodos hidrológicos (seco e chuvoso). Calculamos o Índice de Qualidade de Água (IQA), o Índice de Estado Trófico (ETI) para fósforo e utilizamos uma Análise de Redundância (RDA) para verificar a influência de variáveis ambientais na comunidade de protozoários. Resultados: O IQA mostrou que a qualidade da água foi considerada boa em alguns pontos e considerada ruim em outros pontos, e o ETI para o fósforo classificou o córrego como mesotrófico na maioria dos locais amostrados (média entre 53,09 e 58,35). Foram identificados 19 táxons de amebas testáceas, pertencentes a seis famílias, sendo Difflugiidae, Centropyxidae e Arcellidae as mais especiosas, e 71 táxons de ciliados, distribuídos em 12 ordens, sendo Peniculida a ordem mais representativa, seguida por Euplotida. De acordo com a análise RDA, amostras do período seco foram caracterizadas por maiores valores de densidade bacteriana e concentrações de clorofila-a, fósforo total e nitrogênio total. As amebas testáceas e os ciliados apresentaram valores de abundância maiores em alguns dos meses caracterizados por maior precipitação e em condições de maior produtividade do sistema. Podemos concluir que o córrego Mandacaru, embora fortemente influenciado pela ação antrópica, ainda apresenta uma qualidade de água aceitável. Por fim, enfatizamos que a abundância de protistas foi fortemente influenciada pela produtividade do sistema. Isto foi evidenciado pelas elevadas densidades de protozoários onde houve maior produtividade primária e bacteriana. Assim, esses protistas devem ser considerados em estudos que visem à identificação de organismos que possam indicar impactos antrópicos e qualidade ambiental.

Dolops carvalhoi as a vector of Epistylis sp. between cultivated and wild specimens of Oreochromis niloticus in Brazil / Dolops carvalhoi como vetor de Epistylis sp. entre espécimes cultivados e silvestres de Oreochromis niloticus no Brasil

Epistyliasis has been characterized as an emergent disease which has a great impact on fish farms, especially on Oreochromis niloticus production systems. Although epidemiological important, information about the dispersion of these parasites and their mechanical vectors is scarce. The present study reported the cooccurrence of Epistylis sp. as an epibiont of Dolops carvalhoi, a parasitic crustacean of cultivated/wild specimens (from accidental release) of O. niloticus from a cage fish farm area in the Ilha Solteira Reservoir, Grande River, SP, Brazil. The co-occurrence of Epistylis sp. and D. carvalhoi, and their epibiont relationship registered in this study suppose that the Epistylis may use the crustaceans for dispersion and as mechanical vectors for the dissemination of diseases in wild and cultivated hosts. Moreover, exchange of parasites between wild and cultivated hosts is possible, considering both organisms (protozoan and argulid). Furthermore, the results of the present study demonstrate the need to monitor the areas adjacent to cage fish farms as a preventive measure for the dispersion of pathogens. This is the first report of epibiosis between Epistylis sp. and argulid parasites of cultivated and wild O. niloticus, contributing to knowledge about host-parasite specificity, geographical distribution, dispersion of etiological agents and epidemiology in aquaculture.(AU)

Epistilíase tem sido caracterizada como uma doença emergente de grande impacto nas pisciculturas, especialmente em sistemas de produção de Oreochromis niloticus. Embora seja importante epidemiologicamente, informações sobre a dispersão desses parasitas e seus vetores mecânicos são escassos. O presente estudo relata a coocorrência de Epistylis sp. como um epibionte de Dolops carvalhoi, um crustáceo parasita de espécimes cultivados e silvestres (de escapes acidentais) de O. niloticus em área de piscicultura de tanques-rede no reservatório de Ilha Solteira, Rio Grande, SP, Brasil. A coocorrência de Epistylis sp. e D. carvalhoi, e sua relação epibionte registrada neste estudo, supõem que Epistylis sp. possa utilizar os crustáceos para dispersão e como vetores mecânicos para a disseminação de doenças em hospedeiros silvestres e cultivados. Além disso, a troca de parasitas entre hospedeiros silvestres e cultivados é possível, considerando ambos os organismos (protozoários e argulídeos). Os resultados deste estudo, também demonstram a necessidade de monitorar as áreas adjacentes às pisciculturas como medida preventiva para a dispersão de patógenos. Este é o primeiro relato de epibiose entre Epistylis sp. e parasitas argulídeos de O. niloticus cultivados e silvestres, contribuindo para o conhecimento da especificidade parasitária do hospedeiro, distribuição geográfica, dispersão de agentes etiológicos e epidemiologia na aquicultura.(AU)

Grazing of particle-associated bacteria-an elimination of the non-viable fraction

Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, k value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g) = 0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, g of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086) was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the persistent variants where the viable fraction multiply and release their progeny.(AU)

Structure and dynamics of the protoplankton community in an environmentally protected urban stream

Abstract We aimed to investigate spatial and temporal scales, abundance, and factors that structure the communities of protozoans in a tropical urban stream. Methods: Samples of water for analysis of biological communities (testate amoebae, ciliates and bacteria) and limnological variables were taken in the Mandacaru stream located in the Conservation Unit of Parque do Cinquentenário, in the city of Maringá, Paraná State, Brazil, in two hydrological periods (dry and rainy). We calculated the Water Quality Index (WQI) composed by nine parameters of water quality (dissolved oxygen, thermotolerant coliforms, pH, BOD, water temperature, total nitrogen, total phosphorous, turbidity, and total solids), Trophic State Index (TSI) for phosphorous and we used a Redundancy Analysis (RDA) to verify the influence of environmental variables in the protozoan community. Results: The WQI showed that water quality was considered good in some points and considered bad in other points. The TSI for phosphorus classified the stream as mesotrophic in the majority of sampled sites points (mean between 53.09 and 58.35). We identified 19 taxa of testate amoebae, belonging to six families, being Difflugiidae, Centropyxidae, and Arcellidae those with more species and 71 infrageneric taxa of ciliates, distributed in 12 orders being Peniculida the most representative order, followed by Euplotida. According to RDA analysis, samples of the dry period were characterized by higher values of bacteria density and concentrations of chlorophyll-a, total phosphorous, and total nitrogen. Ciliates and testate amoebae presented higher abundance values in some of the months characterized by higher precipitation and in conditions of higher system productivity. Conclusion: we may conclude that the Mandacaru stream, although strongly influenced by anthropic action, still presents an acceptable water quality. Lastly, we emphasize that protists abundance was strongly influenced by system productivity. This was evidenced by elevated protozoan densities where there was higher primary and bacterial productivity. Thus, these organisms must be considered in studies that aim at the identification of organisms that may indicate anthropic impacts and environmental quality.

Resumo O objetivo foi investigar, em escalas espacial e temporal, a abundância das comunidades de protozoários bem como os fatores intervenientes na estruturação das mesmas em um córrego urbano. Métodos: Amostras de água para análise de comunidades biológicas (amebas testáceas, ciliados e bactérias) e para análise de variáveis limnológicas foram tomadas no córrego Mandacaru localizado na Unidade de Conservação do Parque do Cinquentenário, na cidade de Maringá, Paraná State, Brasil, em dois períodos hidrológicos (seco e chuvoso). Calculamos o Índice de Qualidade de Água (IQA), o Índice de Estado Trófico (ETI) para fósforo e utilizamos uma Análise de Redundância (RDA) para verificar a influência de variáveis ambientais na comunidade de protozoários. Resultados: O IQA mostrou que a qualidade da água foi considerada boa em alguns pontos e considerada ruim em outros pontos, e o ETI para o fósforo classificou o córrego como mesotrófico na maioria dos locais amostrados (média entre 53,09 e 58,35). Foram identificados 19 táxons de amebas testáceas, pertencentes a seis famílias, sendo Difflugiidae, Centropyxidae e Arcellidae as mais especiosas, e 71 táxons de ciliados, distribuídos em 12 ordens, sendo Peniculida a ordem mais representativa, seguida por Euplotida. De acordo com a análise RDA, amostras do período seco foram caracterizadas por maiores valores de densidade bacteriana e concentrações de clorofila-a, fósforo total e nitrogênio total. As amebas testáceas e os ciliados apresentaram valores de abundância maiores em alguns dos meses caracterizados por maior precipitação e em condições de maior produtividade do sistema. Podemos concluir que o córrego Mandacaru, embora fortemente influenciado pela ação antrópica, ainda apresenta uma qualidade de água aceitável. Por fim, enfatizamos que a abundância de protistas foi fortemente influenciada pela produtividade do sistema. Isto foi evidenciado pelas elevadas densidades de protozoários onde houve maior produtividade primária e bacteriana. Assim, esses protistas devem ser considerados em estudos que visem à identificação de organismos que possam indicar impactos antrópicos e qualidade ambiental.

População de protozoários ruminais em novilhos zebuínos alimentados com ou sem volumoso / Population of Protozoa in zebu steers fed with or without bulk

This study aimed to quantify and identify the profile of the rumen protozoa population of beef steers fed with or without roughage. Nellore crossbred steers raised in extensive system on lignified tropical pastures with mineral supplementation and steers confined for 60 days only receiving pelletized concentrate and whole corn kernels were evaluated. After slaughter, rumen fluid was collected and one ml aliquots were diluted in nine ml formaldehyde solution at 10%. The counts of small, medium and large protozoa were held in Sedgewick Rafter chambers and identification of genus was possible after staining lugol and optical microscope with a 40X objective. The concentration of rumen protozoa positively correlated with pH ruminal. Cattle fed without roughage had significantly lower rumen protozoa population (P<0.05). Animals fed roughage had higher occurrence of Dasytrichia genus, Charonina, Entodinum, Diplodinium, Ostracodinium and Epidinium while those fed without bulk, the Buetschilia, Isotricha, Eodinium, Polyplastron, Elyplastron, Metadinium and Enoploplastron were the most frequent genus.(AU)

População de protozoários ruminais em novilhos zebuínos alimentados com ou sem volumoso / Population of Protozoa in zebu steers fed with or without bulk

This study aimed to quantify and identify the profile of the rumen protozoa population of beef steers fed with or without roughage. Nellore crossbred steers raised in extensive system on lignified tropical pastures with mineral supplementation and steers confined for 60 days only receiving pelletized concentrate and whole corn kernels were evaluated. After slaughter, rumen fluid was collected and one ml aliquots were diluted in nine ml formaldehyde solution at 10%. The counts of small, medium and large protozoa were held in Sedgewick Rafter chambers and identification of genus was possible after staining lugol and optical microscope with a 40X objective. The concentration of rumen protozoa positively correlated with pH ruminal. Cattle fed without roughage had significantly lower rumen protozoa population (P<0.05). Animals fed roughage had higher occurrence of Dasytrichia genus, Charonina, Entodinum, Diplodinium, Ostracodinium and Epidinium while those fed without bulk, the Buetschilia, Isotricha, Eodinium, Polyplastron, Elyplastron, Metadinium and Enoploplastron were the most frequent genus.(AU)

Occurrence of suctorian ciliates (Ciliophora, Suctoria) in a polluted creek in Southern Brazil

The Subclass Suctoria encompasses ciliates without cilia during the trophont stage, and that mainly feed on other ciliates, rotifers and microcrustaceans. Suctorians are widely distributed in various habitats and can also be found as epibionts in aquatic invertebrates. Although these organisms are widely distributed, they are poorly studied, mainly in the Southern Hemisphere. In the present study we investigated the occurrence of suctorians ciliates in a polluted creek in Rio Grande do Sul state, Brazil. Using taxonomic keys it was possible to identify one species in the genus Multifasciculatum, one in the genus Tokophryaand two species belonging to the genus Podophrya . All of them are aloricate and freshwater suctorians. These organisms differ in zooid shape, and the distribution of their tentacles in the cell, morphological characteristics of each genus. This study presents the first record of Podophrya fallax , Podophrya sandi , Tokophrya lemnarum, and Multifasciculatum elegansfor the state of Rio Grande do Sul.(AU)

Occurrence of suctorian ciliates (Ciliophora, Suctoria) in a polluted creek in Southern Brazil

The Subclass Suctoria encompasses ciliates without cilia during the trophont stage, and that mainly feed on other ciliates, rotifers and microcrustaceans. Suctorians are widely distributed in various habitats and can also be found as epibionts in aquatic invertebrates. Although these organisms are widely distributed, they are poorly studied, mainly in the Southern Hemisphere. In the present study we investigated the occurrence of suctorians ciliates in a polluted creek in Rio Grande do Sul state, Brazil. Using taxonomic keys it was possible to identify one species in the genus Multifasciculatum, one in the genus Tokophryaand two species belonging to the genus Podophrya . All of them are aloricate and freshwater suctorians. These organisms differ in zooid shape, and the distribution of their tentacles in the cell, morphological characteristics of each genus. This study presents the first record of Podophrya fallax , Podophrya sandi , Tokophrya lemnarum, and Multifasciculatum elegansfor the state of Rio Grande do Sul.

Efeito da inclusão da torta de macaúba na população de protozoários do rúmen de vacas leiteiras / The effect of macauba meal inclusion in the ruminal protozoa population of dairy cows

Avaliaram-se os efeitos da inclusão da torta de macaúba (TM) na dieta sobre a concentração e o perfil da população de protozoários ciliados do rúmen. Foram utilizadas oito vacas Holandesas, dispostas em dois quadrados latinos 4x4 e alimentadas com diferentes níveis de inclusão da TM (0, 100, 200 e 300g kg-1 de matéria seca na dieta total). Para quantificação e identificação dos protozoários, amostras de 1mL do líquido ruminal de cada animal foram diluídas em 9mL de solução de formaldeído a 10%. Após diluições decimais sucessivas em solução salina, os protozoários foram quantificados em câmara de Sedgewick. A identificação foi realizada sob a luz da microscopia óptica, utilizando-se a objetiva de 40x para caracterizar o mínimo de 100 indivíduos por amostra. As concentrações de protozoários pequenos (P<0,01), médios (P=0,05), grandes (P=0,01) e o número total (P<0,01) apresentaram comportamento linear decrescente com o aumento dos níveis de inclusão da TM nas dietas. Foram encontradas características morfológicas típicas de 16 gêneros de protozoários ciliados, sendo os gêneros Entodinium e Eodinium os mais frequentes no líquido ruminal dos animais avaliados. O perfil da população de protozoários ciliados sofreu pequenas alterações com a inclusão da TM, sendo observada alteração na participação percentual dos gêneros Charonina (P = 0,03) e Polyplastron (P<0,01). A utilização da TM na dieta de bovinos promove redução na concentração e modificação no perfil da população de protozoários ciliados do rúmen(AU)

The effects of meal macaúba (MM) inclusion on the concentration and profile of the ciliate protozoa of the bovine rumen were evaluated. Eight Holstein cows were used during second lactation, with average 480 kg of body weight, arranged in two 4x4 Latin squares simultaneously and fed four diets with different concentrations of the MM (0, 100, 200 and 300 g kg-1). For identification and quantification of protozoa, samples of ruminal fluid from each animal with 1 ml were diluted in 9mL of 10% formaldehyde. After consecutive decimal dilutions in saline solution, protozoa were assessed in a Sedgewick chamber. The identification was carried out under the optical light microscope using a 40x objective to characterize at least 100 individuals per sample. The concentrations of small (P<0.01), medium (P=0.05), large (P= 0.01), and the total number (P<0.01) of protozoa decreased linearly with the increasing MM inclusion. Morphological characteristics typical of 16 genera of ciliates were found, being the Entodinium spp. and Eodinium spp. the most frequent in the rumen fluid of animals evaluated. The profile of the population of ciliated protozoa suffer minor changes with the addition of MM, with a change in the percentage share of Charonina spp. (P = 0.03) and Polyplastron spp. (P <0.01). The use of the MM in the cattle diet promotes reduction in the concentration and change in the profile of the population of rumen ciliates protozoa(AU)

Protozoans bacterivory in a subtropical environment during a dry/cold and a rainy/warm season

In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF) in a subtropical freshwater reservoir (Monjolinho reservoir -São Carlos -Brazil) during one year period, in order to verify their importance as consumers and controllers of bacteria in two seasons, a dry/cold and a rainy/warm one. For this purpose, in situ bacterivory experiments were carried out bimonthly using fluorescently labeled bacteria with 5-(4,6 diclorotriazin-2yl) aminofluorescein (DTAF). Although ciliates have shown the highest individual ingestion and clearance rates, bacterivory was dominated by HNF, who showed higher population ingestion rates (mean of 9,140 bacteria h-1mL-1) when compared to ciliates (mean of 492 bacteria h-1mL-1). The greater predation impact on bacterial communities was caused mainly by the small HNF (< 5 µm) population, especially in the rainy season, probably due to the abundances of these organisms, the precipitation, trophic index state and water temperature that were higher in this period. Thus, the protozoan densities together with environmental variables were extremely relevant in determining the seasonal pattern of bacterivory in Monjolinho reservoir.

Protozoans bacterivory in a subtropical environment during a dry/cold and a rainy/warm season

In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF) in a subtropical freshwater reservoir (Monjolinho reservoir -São Carlos -Brazil) during one year period, in order to verify their importance as consumers and controllers of bacteria in two seasons, a dry/cold and a rainy/warm one. For this purpose, in situ bacterivory experiments were carried out bimonthly using fluorescently labeled bacteria with 5-(4,6 diclorotriazin-2yl) aminofluorescein (DTAF). Although ciliates have shown the highest individual ingestion and clearance rates, bacterivory was dominated by HNF, who showed higher population ingestion rates (mean of 9,140 bacteria h-1mL-1) when compared to ciliates (mean of 492 bacteria h-1mL-1). The greater predation impact on bacterial communities was caused mainly by the small HNF (< 5 µm) population, especially in the rainy season, probably due to the abundances of these organisms, the precipitation, trophic index state and water temperature that were higher in this period. Thus, the protozoan densities together with environmental variables were extremely relevant in determining the seasonal pattern of bacterivory in Monjolinho reservoir.(AU)

The importance of protozoan bacterivory in a subtropical environment (Lobo-Broa Reservoir, SP, Brazil) / A importância da bacterivoria por protozoários em um ambiente subtropical (Reservatório do Lobo-Broa, SP, Brasil)

This study evaluated the importance of heterotrophic nanoflagellates (HNF) and ciliates bacterivory in a mesotrophic subtropical environment (Lobo-Broa Reservoir, Brazil) by the quantification of their ingestion rates. The in situ experiments using fluorescently labelled bacteria (FLB) were carried out bimonthly over one year (three surveys in the dry season and three in the rainy one) at the sub-surface of two sampling points that have different trophic degrees. The ingestion rates for both ciliates and HNF were higher in the meso-eutrophic region (point 2) due to the higher water temperatures, which accelerate the metabolism of protozoans and the higher bacteria densities. Concerning total protozoan bacterivory, the HNF had the greatest grazing impact on bacterial community, especially the HNF <5µm. The data showed that HNF grazing, in addition to regulating the bacteria abundance, also induced changes to the bacterial community structure, such as increasing size and numbers of bacterial filaments. The ciliates were also important to the system bacterivory, especially in point 2, where there were high densities and ingestion rates. The protozoan bottom-up control was more important in the dry season and the top-down control was more important in the rainy season, so, these two forces are equally important to the bacterial abundance regulation in this reservoir in an annual basis.(AU)

Este estudo avaliou a importância da bacterivoria por nanoflagelados heterotróficos (NFH) e ciliados em um ambiente subtropical mesotrófico (Reservatório do Lobo-Broa, Brasil) pela quantificação de suas taxas de ingestão. Os experimentos in situ utilizando bactérias marcadas por fluorescência (FLB) foram realizados bimestralmente durante um ano (três estudos no período seco e três no período chuvoso) na superfície de dois pontos de coleta que apresentam graus de trofia diferentes. As taxas de ingestão, tanto para os ciliados quanto para os NHF, foram maiores no ponto 2 (P2) devido provavelmente as maiores temperaturas da água, que aceleram o metabolismo dos protozoários, e as maiores densidades de bactérias. Em relação à bacterivoria total por protozoários, as populações de NFH causaram maior impacto de predação sobre a comunidade bacteriana do reservatório, principalmente os NFH menores que 5µm. Os dados indicaram que a predação por NFH, além de regular a abundância de bactérias, provavelmente também induziu modificações na estrutura da comunidade bacteriana, como o aumento do tamanho e da quantidade de filamentos bacterianos. Os ciliados também contribuíram significativamente para a bacterivoria no sistema, principalmente no P2, onde apresentaram altas densidades e taxas de ingestão. O controle bottom-up teve maior importância no período seco e o controle top-down maior importância no período chuvoso, assim, estas duas forças são igualmente importantes na regulação da abundância bacteriana neste reservatório em uma base anual.(AU)

Morphology and 18S rDNA gene sequence of Spirostomum minus and Spirostomum teres (Ciliophora: Heterotrichea) from Rio de Janeiro, Brazil

Species of Spirostomum Ehrenberg, 1838 are widely used as model organisms in ecological studies of environmental impacts and symbioses between ciliates and human pathogenic bacteria. However, the taxonomy of this genus is confused by the superficiality of the morphological descriptions of its included species, and the use of only a few characters for their differentiation. The present study provides details of total infraciliature, nuclear apparatus, morphometric data and 18S rDNA gene sequences of Spirostomum teres Claparède & Lachmann, 1858 and Spirostomum minus Roux, 1901, isolated from a sewage treatment plant and a freshwater lake in the city of Rio de Janeiro, Brazil, respectively. For the morphological descriptions of S. teres and S. minus, living cells were observed using bright-field and differential interference contrast (DIC) microscopy, the total infraciliature and nuclear apparatus were revealed by staining with protargol, and ciliary patterns were observed also with scanning electron microscopy (SEM). The complete sequences of the 18S rDNA of S. teres and S. minus were obtained using eukaryotic universal primers, and then compared with sequences of other species and populations of Spirostomum deposited in the GenBank database. Living S. minus measured 400-800 µm in length and 55-115 µm in width, with the following characteristics: adoral zone of membranelles approximately 112 µm long; inconspicuous paroral kinety; 30-40 kineties in somatic ciliature; moniliform macronucleus with 9-25 nodes, approximately 12 micronuclei; single and posterior contractile vacuole; and yellow-brown cytoplasm. Living and fully extended S. teres measured approximately 250 µm in length and 65 ìm in width, with the following characteristics: adoral zone of membranelles approximately 92 µm long; approximately 30 somatic kineties; compact macronucleus, approximately five micronuclei; macronuclear groove present; single and posterior contractile vacuole; and colorless cytoplasm. Evidence from 18S rDNA sequences confirms the identification of S. teres and suggests the existence of cryptic species closely related to S. minus. The use of silver impregnation technique (protargol) allowed the observation and description of a greater number of characters in S. minus and S. teres, thus assisting the research that require identification of these species.

Morphology and 18S rDNA gene sequence of Spirostomum minus and Spirostomum teres (Ciliophora: Heterotrichea) from Rio de Janeiro, Brazil

Species of Spirostomum Ehrenberg, 1838 are widely used as model organisms in ecological studies of environmental impacts and symbioses between ciliates and human pathogenic bacteria. However, the taxonomy of this genus is confused by the superficiality of the morphological descriptions of its included species, and the use of only a few characters for their differentiation. The present study provides details of total infraciliature, nuclear apparatus, morphometric data and 18S rDNA gene sequences of Spirostomum teres Claparède & Lachmann, 1858 and Spirostomum minus Roux, 1901, isolated from a sewage treatment plant and a freshwater lake in the city of Rio de Janeiro, Brazil, respectively. For the morphological descriptions of S. teres and S. minus, living cells were observed using bright-field and differential interference contrast (DIC) microscopy, the total infraciliature and nuclear apparatus were revealed by staining with protargol, and ciliary patterns were observed also with scanning electron microscopy (SEM). The complete sequences of the 18S rDNA of S. teres and S. minus were obtained using eukaryotic universal primers, and then compared with sequences of other species and populations of Spirostomum deposited in the GenBank database. Living S. minus measured 400-800 µm in length and 55-115 µm in width, with the following characteristics: adoral zone of membranelles approximately 112 µm long; inconspicuous paroral kinety; 30-40 kineties in somatic ciliature; moniliform macronucleus with 9-25 nodes, approximately 12 micronuclei; single and posterior contractile vacuole; and yellow-brown cytoplasm. Living and fully extended S. teres measured approximately 250 µm in length and 65 ìm in width, with the following characteristics: adoral zone of membranelles approximately 92 µm long; approximately 30 somatic kineties; compact macronucleus, approximately five micronuclei; macronuclear groove present; single and posterior contractile vacuole; and colorless cytoplasm. Evidence from 18S rDNA sequences confirms the identification of S. teres and suggests the existence of cryptic species closely related to S. minus. The use of silver impregnation technique (protargol) allowed the observation and description of a greater number of characters in S. minus and S. teres, thus assisting the research that require identification of these species.

Morphology and 18S rDNA gene sequence of Spirostomum minus and Spirostomum teres (Ciliophora: Heterotrichea) from Rio de Janeiro, Brazil

Species of Spirostomum Ehrenberg, 1838 are widely used as model organisms in ecological studies of environmental impacts and symbioses between ciliates and human pathogenic bacteria. However, the taxonomy of this genus is confused by the superficiality of the morphological descriptions of its included species, and the use of only a few characters for their differentiation. The present study provides details of total infraciliature, nuclear apparatus, morphometric data and 18S rDNA gene sequences of Spirostomum teres Claparède & Lachmann, 1858 and Spirostomum minus Roux, 1901, isolated from a sewage treatment plant and a freshwater lake in the city of Rio de Janeiro, Brazil, respectively. For the morphological descriptions of S. teres and S. minus, living cells were observed using bright-field and differential interference contrast (DIC) microscopy, the total infraciliature and nuclear apparatus were revealed by staining with protargol, and ciliary patterns were observed also with scanning electron microscopy (SEM). The complete sequences of the 18S rDNA of S. teres and S. minus were obtained using eukaryotic universal primers, and then compared with sequences of other species and populations of Spirostomum deposited in the GenBank database. Living S. minus measured 400-800 µm in length and 55-115 µm in width, with the following characteristics: adoral zone of membranelles approximately 112 µm long; inconspicuous paroral kinety; 30-40 kineties in somatic ciliature; moniliform macronucleus with 9-25 nodes, approximately 12 micronuclei; single and posterior contractile vacuole; and yellow-brown cytoplasm. Living and fully extended S. teres measured approximately 250 µm in length and 65 ìm in width, with the following characteristics: adoral zone of membranelles approximately 92 µm long; approximately 30 somatic kineties; compact macronucleus, approximately five micronuclei; macronuclear groove present; single and posterior contractile vacuole; and colorless cytoplasm. Evidence from 18S rDNA sequences confirms the identification of S. teres and suggests the existence of cryptic species closely related to S. minus. The use of silver impregnation technique (protargol) allowed the observation and description of a greater number of characters in S. minus and S. teres, thus assisting the research that require identification of these species.(AU)

Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil) / Variação sazonal da comunidade protozooplanctônica em um ambiente oligotrófico tropical (reservatório de Ilha Solteira, Brasil)

The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L1), while the lowest was in the dry/cold (2016.0 ind L1). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).(AU)

A variação sazonal da comunidade protozooplanctônica (ciliados e amebas testáceas) foi estudada em um reservatório oligotrófico tropical no Brasil, que estava sob a influência de dois períodos climáticos contrastantes (chuvoso/quente e seco/frio). O objetivo deste estudo foi avaliar os efeitos destas mudanças climáticas sobre as variáveis físicas, químicas e biológicas na dinâmica desta comunidade. A maior densidade média de protozoários total ocorreu no período chuvoso e quente (5683,2 ind L1), enquanto a menor foi no período seco e frio (2016,0 ind L1). Considerando-se as variações sazonais, os grupos de protozoários que são verdadeiramente planctônicos, como os oligotrichs (Spirotrichea), predominaram no período seco, enquanto que, no período chuvoso, em razão da entrada de material e da ressuspensão do sedimento, os protozoários sésseis do grupo Peritrichia foram os mais importantes. Os protozoários dominantes foram Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. e Halteria grandinella. As maiores densidades de H. grandinella foram associadas com condições de águas mais oxigenadas e transparentes, enquanto que as maiores densidades de C. annulata ocorreram em locais com alta turbidez, pH e índice de estado trófico (IET). O estudo demonstrou que a densidade e a composição de espécies, e os grupos protozooplanctônicos do reservatório sofreram variação sazonal por causa das variáveis ambientais principalmente temperatura, além de turbidez, transparência da água, oxigênio dissolvido e IET e das variáveis biológicas, como, por exemplos, características morfológicas, hábitos alimentares e estratégias de escape à predação das espécies.(AU)

Modelagem estatística para estimação da população de protozoários ruminais em função da relação volumoso: concentrado na dieta e da presença de aditivos

The objective was to develop statistical models to estimate variations in the population of Protozoa in the light of forage: concentrate ratio and the presence or absence of additives in the diet. Excel spreadsheets with data on diet composition, presence and absence of additives and the number of protozoa in the rumen of cattle for work done in Brazil were using. These variables were used and tested to obtain the equation for predicting the profile of the population of protozoa. The models obtained were checked by residual analysis and selection of variables was performed considering the significance level of 5%. It was found for the total count of protozoa and Entodinium that the increased proportion of large positive effect and additive ionophores had a negative effect. The use of statistical models can provide a better understanding of dietary factors on the microbiota of the rumen and on the animal.

Objetivou-se com a realização deste trabalho desenvolver modelos estatísticos para estimar as variações da população de protozoários ruminais em função da relação volumoso:concentrado e da presença ou não de aditivos na dieta. Foram construídas planilhas mediante a utilização do software Excel com dados referentes à composição da dieta, presença e ausência de aditivos e do número de protozoários do rúmen de bovinos de 23 artigos científicos e três teses realizados no Brasil. Estas variáveis foram utilizadas e testadas para obtenção da equação para predição do perfil da população de protozoários. Os modelos estatísticos obtidos foram verificados por análise residual e a seleção das variáveis foi realizada considerando o nível de significância de 5% de probabilidade do erro experimental. Verificou-se que dietas com maior proporção de volumosos favorecem o incremento na população de protozoários totais e em particular, de Entodinium, enquanto a presença de ionóforos reduz o número desses microorganismos ruminais. O modelo estatísticos desenvolvido pode auxiliar na identificação antecipada de fatores nutricionais limitantes para o desenvolvimento da microbiota ruminal.

Simulação dos efeitos de fatores dietéticos sobre a população de protozoários ruminais

The objective was to develop statistical models that can estimate the variations of the rumen protozoa population through changes in diet, using as parameters: neutral detergent fiber and crude protein, dry matter intake and pH, and to verify whether the variables weight and race influence on the population of protozoa in the rumen. Were built using Excel spreadsheets and recorded data on the aforementioned parameters and the profile of the rumen microbiota. These variables were used and tested to obtain the equations for predicting the profile of the microbiota. The models obtained were checked by residual analysis and selection of variables was performed considering the significance level of 5%, using the software MINITAB Release 15 (2010). The regression equations obtained from the analyzed data may imply that: there was an increase in the number of total protozoa proportional to the elevation of pH, the variables race, weight and additives exerted a significant effect on the protozoa population totals, as increased if dry matter intake decreased the number Protozoa; increasing the neutral detergent fiber content in the diet promoted an increase in the number of protozoa, the higher the crude protein, the lower the total number of protozoa. The models allow to estimate the number of parasites in the light of these variables: pH, dry matter intake, neutral detergent fiber and crude protein contents of diet and the presence or absence of additives.

Objetivouse desenvolver modelos estatísticos que possam estimar as variações da população de protozoários ruminais mediante alterações na dieta, por meio de utilização dos parâmetros: teores de fibra em detergente neutro e proteína bruta, consumo de matéria seca e pH, bem como verificar se as variáveis peso vivo e raça exercem influência sobre a população de protozoários do rúmen. Foram construídas planilhas por meio do software Excel e registrados dados referentes aos parâmetros acima mencionados e sobre o perfil da microbiota ruminal. Estas variáveis foram utilizadas e testadas para obtenção das equações para predição do perfil da microbiota. Os modelos estatísticos obtidos foram verificados por análise residual e para a seleção das variáveis foi considerado o nível de significância de 5%, mediante a utlização do software MINITAB Versão 15 (2010). As equações de regressão obtidas a partir dos dados analisados permitem inferir que: ocorreu um aumento no número de protozoários totais proporcional à elevação do pH; as variáveis raça, peso e aditivos exerceram efeito significativo sobre a população de protozoários totais; à medida que elevouse o consumo de matéria seca, diminuiu o número de protozoários ruminais; o aumento do teor de fibra em detergente neutro na dieta promoveu incremento no número de protozoários; quanto maior o teor de proteína bruta, menor o número de protozoários totais. Os modelos obtidos permitem estimar o número de protozoários em função das variáveis raça, peso, pH, consumo de matéria seca, teores fibra em detergente neutro e proteína bruta da dieta e presença ou ausência de aditivos.

DEGRADAÇÃO RUMINAL DE DIETAS À BASE DE MILHO EM SUBSTITUIÇÃO AO GRÃO DE SORGO COM ALTO TANINO

Objetivou-se avaliar os efeitos da substituição do milho pelo grão de sorgo com alto tanino sobre o consumo, digestibilidade, parâmetros ruminais (pH, N-NH3 e AGVs), degradabilidade da matéria seca do grão de sorgo com alto tanino e contagem de protozoários ciliados em bovinos fistulados no rúmen. Foram utilizados 4 bovinos adultos machos castrados, mestiços Holandês x Zebu, com peso vivo de 518,8 ± 30,6 Kg, distribuídos em um delineamento quadrado latino (DQL) seguindo modelo 4x4. Os tratamentos experimentais consistiram na substituição de milho por grão de sorgo com alto tanino em níveis crescentes de 0, 33, 67 e 100% na matéria seca (%MS) e como fonte de volumoso, silagem de capim elefante. Todas as análises foram feitas utilizando o pacote estatístico (SAS, 2009. Institute Inc., Cary, NC). Não houve efeito significativo sobre o consumo de MS e nutrientes (P>0,05) em função dos níveis de substituição do milho pelo sorgo. Verificou-se efeito linear decrescente (P<0,05) sobre o coeficiente de digestibilidade apenas da PB e FDNcp a medida que se aumentou da proporção do sorgo nas dietas.As mensurações dos parâmetros ruminais foram realizadas antes, 2, 4 e 6 horas após a suplementação.O pH do rúmen variou entre 6,1 e 6,7 durante os horários de coleta, não havendo diferença significativa entre os tratamentos (P=0,57) nem para interação tratamento x hora (P=0,24), porém o horário de coleta apresentou efeito quadrático (P<0,05), atingindo os menores valores quatro horas após o fornecimento da ração. Os valores de N-NH3 variaram entre 3,18 e 20,97 mg/dL durante os horários de coleta, não ocorrendo diferença significativa entre os tratamentos (P=0,35), ou para interação tratamento x hora (P=0,66), no entanto, apresentou efeito quadrático em relação ao horário de coleta (P<0,05), com pico de produção 2 horas após o fornecimento da ração. As concentrações dos AGVs (acético, propiônico e butirico) e a relação acetato/propionato não diferiram entre os tratamentos (P>0,05), nem houve interação entre tratamento x horário (P>0,05) para estas variáveis, no entanto, ácido acético e propiônico apresentaram efeito linear crescente (P<0,05) para os horários de coleta ao se substituir milho por sorgo. A contagem de protozoários ciliados reduziu linearmente (P<0,05) ao se elevar o nível de sorgo nas dietas. O grão de milho triturado pode ser substituído pelo grão de sorgo com alto tanino em dietas para bovinos adultos.

This study aimed to evaluate the effects of replacing corn with sorghum grain with high tannin on the intake, digestibility, ruminal parameters (pH, N-NH3 and VFA) degradability of the dry matter of sorghum grain with high tannin and counting of ciliated protozoa in the rumen cannulated cattle. We used four adult cattle castrated male crossbred Holstein x Zebu with a live weight of 518.8 ± 30.6 kg, distributed in a Latin square design (DQL) following 4x4 model. The treatments consisted in the replacement of corn by sorghum grain with high tannin in increasing levels of 0, 33, 67 and 100% of dry matter (% MS) and as a source of roughage, silage of elephant grass. All analyzes were performed using the statistical package (SAS Institute Inc. 2009, Cary, NC). There was no significant effect on DM intake and nutrient (P> 0.05) on the basis of corn replacement levels for sorghum. There was a decreasing linear effect (P <0.05) on the digestibility of CP and only NDFap the measure that increased the proportion of sorghum in dietas. As measurements of ruminal parameters were performed before, 2, 4 and 6 hours after suplementação.O rumen pH ranged between 6.1 and 6.7 during the collection times, with no significant difference between treatments (P = 0.57) or for treatment x time interaction (P = 0.24) But the collection schedule showed a quadratic effect (P <0.05), reaching the lowest values four hours after delivery of the feed. The N-NH 3 values ranged between 3.18 and 20.97 mg / dL during the collection times, no significant differences between treatments (P = 0.35), or interaction treatment x time (P = 0, 66), however, showed a quadratic effect in relation to collection time (P <0.05), with peak production two hours after delivery of the feed. The concentrations of AGVs (acetic, propionic and butyric) and the acetate / propionate ratio did not differ between treatments (P> 0.05), nor was no interaction between treatment x time (P> 0.05) for these variables, however , acetic and propionic acid showed increasing linear effect (P <0.05) for the collection times to replace corn by sorghum. The ciliate protozoa count decreased linearly (P <0.05) when raising the level of sorghum in the diets. The ground corn can be replaced by grain sorghum with high tannin diets to adult cattle.