Efecto Ecotoxicológico de la Mezcla de Aroclor 1254 y Plomo en el Bioindicador Daphnia magna / Ecotoxicological effect of the mixture of Aroclor 1254 and lead in the bioindicator Daphnia magna / Efeito ecotoxicológico da mistura de aroclor 1254 e chumbo no bioindicador Daphnia magna

Resumen Introducción: el bioensayo con la especie bioindicadora Daphnia magna Strauss, 1820 posibilita obtener el efecto ecotoxicológico agudo individual y en mezcla de diversos tóxicos químicos mediante la concentración letal media (CL50). Objetivo: determinar el efecto ecotoxicológico de la mezcla de aroclor 1254 y del plomo (Pb2+) sobre D. magna. Materiales y Métodos: se midió la CL50 siendo aroclor 1254 > Pb2+, y ulteriormente la concentración sin efecto ecológico (PNEC) para el efecto individual y en mezcla. Se contrastaron los valores de PNEC con la categoría 4 - E1 (lagunas y lagos) y E2 (ríos) del Estándar de Calidad Ambiental Peruano (Decreto Supremo N° 004 2017-MINAM -Perú). Resultados: los valores de CL50 disminuyeron de forma gradual a 48 h de exposición para ambos compuestos en forma individual y en mezcla. Se calculó la proporción - sinergia (PS) en relaciones de 1:1, 3:2 y 4:1 (aroclor 1254: Pb2+), obteniéndose mayores valores de PS en 3:2 y 4:1 en contrastación a 1:1. Conclusiones: la concentración de aroclor 1254 estimada de PNEC es similar al valor de la conservación del ambiente acuático categoría 4 - E1 y E2, y la concentración máxima para Pb2+ no es adecuada y debe reducirse para fortalecer la conservación de la biota acuática. Finalmente, el bioindicador D. magna determinó idóneamente la mezcla de aroclor 1254 y Pb2+.

Abstract Introduction: the bioassay with the bioindicator species Daphnia magna Strauss, 1820 makes it possible to obtain the individual acute ecotoxicological effect and in a mixture of various chemical toxics by means of the mean lethal concentration (LC50). Objective: to determine the ecotoxicological effect of the mixture of aroclor 1254 and lead (Pb2+) on D. magna. Materials and Methods: LC50 was measured with arochlor 1254> Pb2+, and subsequently the concentration without ecological effect (PNEC) for the individual effect and as a mixture. PNEC values were contrasted with category 4-E1 (lagoons and lakes) and E2 (rivers) of the Peruvian Environmental Quality Standard (Supreme Decree No. 004 2017-MINAM-Peru). Results: LC50 values gradually decreased after 48 h of exposure for both compounds individually and as a mixture. The proportion-synergy (PS) was calculated in ratios of 1:1, 3:2 and 4:1 (arochlor 1254: Pb2+), obtaining higher PS values in 3:2 and 4:1 in contrast to 1:1. Conclusions: the PNEC estimated arochlor 1254 concentration is similar to the conservation value of the aquatic environment category 4-E1 and E2, and the maximum concentration for Pb2+ is not adequate and should be reduced to strengthen the conservation of aquatic biota. Finally, the bioindicator D. magna ideally determined the mixture of aroclor 1254 and Pb2+.

Resumo Introdução: o bioensaio com as espécies bioindicadoras Daphnia magna Strauss, 1820 permite obter o efeito ecotoxicológico agudo individual e numa mistura de várias toxinas químicas por meio da concentração letal média (CL50). Objetivo: determinar o efeito ecotoxicológico da mistura de arocloro 1254 e chumbo (Pb2+) sobre D. magna. Materiais e Métodos: a CL50 foi medida com arocloro 1254>Pb2+, e posteriormente a concentração sem efeito ecológico (PNEC) para o efeito individual e como mistura. Os valores do PNEC foram contrastados com a categoria 4-E1 (lagoas e lagos) e E2 (rios) do Padrão de Qualidade Ambiental Peruano (Decreto Supremo n° 004 2017-MINAM-Peru). Resultados: Os valores de LC50 diminuíram gradualmente após 48 h de exposição para ambos os compostos individualmente e como uma mistura. A proporção-sinergia (PS) foi calculada em proporções de 1:1, 3:2 e 4:1 (arocloro 1254: Pb2+), obtendo-se valores de PS mais altos em 3:2 e 4:1 em contraste com 1:1. Conclusões: a concentração estimada de arocloro 1254 do PNEC é semelhante ao valor de conservação do ambiente aquático categoria 4-E1 e E2, e a concentração máxima de Pb2+ não é adequada e deve ser reduzida para fortalecer a conservação da biota aquática. Finalmente, o bioindicador D. magna determinou idealmente a mistura de arocloro 1254 e Pb2+.

Contaminación en el Lago de Tota, Colombia: toxicidad aguda en Daphnia magna (Cladocera: Daphniidae) e Hydra attenuata (Hydroida: Hydridae) / Pollution in Lago de Tota, Colombia: acute toxicity on Daphnia magna (Cladocera: Daphniidae) and Hydra attenuata (Hydroida: Hydridae)

Resumen La cuenca del Lago de Tota ha sido modificada por diversas actividades humanas, como deforestación, piscicultura y el monocultivo de cebolla larga (Allium fistulosum) con un elevado uso de agroquímicos y gallinaza cruda, causando deterioro de las características ecológicas del sistema léntico de alta montaña más grande de Colombia. En este trabajo se implementaron pruebas de toxicidad para determinar posibles efectos deletéreos sobre H. attenuata y D. magna. Se aclimataron los organismos y validaron los ensayos de toxicidad en condiciones de laboratorio, posteriormente se realizó la evaluación de agua y sedimentos (elutriados) provenientes de afluentes de la cuenca del lago: Hato Laguna, El Tobal, Los Pozos y Agua Blanca, durante dos periodos hidroclimáticos contrastantes. Se evidenció una mayor sensibilidad con los ensayos en H. attenuata, ya que señalan que aguas y elutriados de Hato Laguna, El Tobal y Los Pozos generaron respuestas de subletalidad (Kruskal-Wallis; P < 0.05) y letalidad. Se registra presencia positiva de al menos cinco plaguicidas no cuantificados antes en la cuenca (clorotalonilo, aldrin, dieldrin, DDT y congéneres). Estos resultados indicarían una potencial influencia negativa de las actividades antropogénicas sobre organismos acuáticos nativos, con posibles consecuencias sobre la composición, estructura y función de las comunidades hidrobiológicas.(AU)

Abstract Lago de Tota basin is currently being impacted by human activities like agriculture, deforestation, large-scale fish farming and monoculture of onion long (Allium fistulosum) with high use of agrochemicals and chicken manure that contaminate runoff to aquatic systems in the largest high mountain lake in Colombia. We implemented toxicity tests to evaluate possible deleterious effects of contaminants on H. attenuata and D. magna, model organisms commonly used in aquatic contamination assessment. Firstly, the organisms were acclimated and toxicity tests were validated in laboratory conditions. Later, water and sediments (elutriates) were evaluated from tributaries of Lago de Tota basin: Hato Laguna, El Tobal, Los Pozos, and Agua Blanca stream, during two contrasting hydroclimatic periods. In addition, pesticides in sediments were evaluated with chromatography, spectrometry and ultraviolet detection techniques. Acute toxicity tests showed that H. attenuata was more sensitive than D. magna, as it showed sublethal (Kruskal-Wallis; P < 0.05) and lethal responses to exposure to waters and elutriates from Hato Laguna, El Tobal, and Los Pozos. At least five pesticides not quantified before in the basin were detected in chemical analyses (chlorothalonil, aldrin, dieldrin, DDT y congeners). These results indicate that anthropogenic activities have a potentially negative influence in aquatic communities composition, structure, and function, it´s demand attention in future research.(AU)

Toxicities of Four Parabens and Their Mixtures to Daphnia magna and Aliivibrio fischeri

The objective of this study was to determine toxicities of four parabens (methyl paraben, MP; ethyl paraben, EP; n-propyl paraben, PP; and n-butyl paraben; BP) and their mixtures to two aquatic microorganisms, Daphnia magna and Aliivibrio fischeri. Parabens are one of the widely used preservatives for personal care products, such as cosmetics, pharmaceuticals and food also. First, each paraben was treated to D. magna to measure the toxicity levels as LC₂₀ and LC₅₀. The results showed their value of MP (25.2 mg/L, 73.4 mg/L), EP (18.4 mg/L, 43.7 mg/L), PP (10.4 mg/L, 21.1 mg/L) and BP (3.3 mg/L, 11.2 mg/L). Then, each of the parabens was treated to A. fischeri and calculated their EC₂₀ and EC₅₀ by bioluminescence inhibition test. The results showed the values of MP (2.93 mg/L, 16.8 mg/L), EP (1.18 mg/L, 6.74 mg/L), PP (0.51 mg/L, 5.85 mg/L) and BP (0.21 mg/L, 2.34 mg/L). These four parabens belong to the group classified as being ‘harmful to aquatic organisms’ (above 10 mg/L, below 100 mg/L). After measuring the toxicity, EC₂₀ values of two or more parabens were tested in order to investigate their toxicity. A total of ten combinations of four parabens were tested. As a result, the bioluminescence inhibition test of A. fischeri showed that the toxicity of mixture parabens was stronger than that of a single compound and combinations of three parabens showed the highest bioluminescence inhibition. These results showed that independent toxicity of paraben was maintained. Therefore, it can be predictable that the toxicity of paraben is getting stronger by the addition of other parabens.

Toxicities of Four Parabens and Their Mixtures to Daphnia magna and Aliivibrio fischeri

The objective of this study was to determine toxicities of four parabens (methyl paraben, MP; ethyl paraben, EP; n-propyl paraben, PP; and n-butyl paraben; BP) and their mixtures to two aquatic microorganisms, Daphnia magna and Aliivibrio fischeri. Parabens are one of the widely used preservatives for personal care products, such as cosmetics, pharmaceuticals and food also. First, each paraben was treated to D. magna to measure the toxicity levels as LC₂₀ and LC₅₀. The results showed their value of MP (25.2 mg/L, 73.4 mg/L), EP (18.4 mg/L, 43.7 mg/L), PP (10.4 mg/L, 21.1 mg/L) and BP (3.3 mg/L, 11.2 mg/L). Then, each of the parabens was treated to A. fischeri and calculated their EC₂₀ and EC₅₀ by bioluminescence inhibition test. The results showed the values of MP (2.93 mg/L, 16.8 mg/L), EP (1.18 mg/L, 6.74 mg/L), PP (0.51 mg/L, 5.85 mg/L) and BP (0.21 mg/L, 2.34 mg/L). These four parabens belong to the group classified as being ‘harmful to aquatic organisms’ (above 10 mg/L, below 100 mg/L). After measuring the toxicity, EC₂₀ values of two or more parabens were tested in order to investigate their toxicity. A total of ten combinations of four parabens were tested. As a result, the bioluminescence inhibition test of A. fischeri showed that the toxicity of mixture parabens was stronger than that of a single compound and combinations of three parabens showed the highest bioluminescence inhibition. These results showed that independent toxicity of paraben was maintained. Therefore, it can be predictable that the toxicity of paraben is getting stronger by the addition of other parabens.

Evaluation of eugenol toxicity in bioassays with test-organisms / Avaliação da toxicidade do eugenol em bioensaios com organismos-teste

ABSTRACT: Fish in both natural and farming conditions are exposed to stress of capture, handling, transport or treatment that provoke low zootechnical performance. Anesthetics like eugenol obtained from clove oil have been used strategically not only in freshwater but also in marine and estuarine fish in order to reduce the stress. Apart from the eugenol indication as anesthetic and its low toxicity for animals, its environment action is not clear. Bioassays or ecotoxicity tests with indicator organisms are used to evaluate the mode of action of the pollutants in the environment. The aim of this study was to test the acute toxicity of eugenol using the microcrustacean Daphnia magna and the bacterium Aliivibrio fischeri, and also its chronic toxicity for the algae Desmodesmus subspicatus. Eugenol in the concentrations of 50, 75 and 100mg L-1 were toxic to tested indicator organisms.

RESUMO: Os peixes, seja em ambiente natural ou em piscicultura, sofrem efeito do estresse na captura, manejo, transporte ou tratamentos que provocam baixo desempenho zootécnico. Anestésicos, como o eugenol, obtido a partir do óleo de cravo, tem sido usado estrategicamente não só em peixes de água doce, mas também em peixes marinhos e estuarinos para reduzir o estresse. Apesar da indicação de eugenol como anestésico em peixes e da sua baixa toxicidade para estes animais, não se tem clareza da sua ação sobre o ambiente. Bioensaios ou testes de ecotoxicidade com organismos indicadores são usados em para avaliar o modo de ação de poluentes no ambiente. O objetivo deste estudo foi testar a toxicidade aguda do eugenol utilizando o microcrustáceo Daphnia magna e a bactéria Aliivibrio fischeri e sua toxicidade crônica para alga Desmodesmus subspicatus. O eugenol, nas concentrações de 50, 75 e 100mg L-1, foi tóxico para organismos indicadores testados.

Acute toxicity assessment of camphor in biopesticides by using Daphnia magna and Danio rerio

OBJECTIVES: An ecofriendly alternative to chemical pesticides is bio-pesticides, which are derived from natural sources. The interest in bio-pesticides is based on the disadvantages associated with chemical pesticides. METHODS: We conducted acute toxicity assessments of camphor, a major component of bio-pesticides, by using Daphnia magna (D. magna) as well as assessed the morphological abnormalities that occurred in Danio rerio (D. rerio) embryos. RESULTS: The median effective concentration of camphor on D. magna after 48 hours was 395.0 muM, and the median lethal concentration on D. rerio embryos after 96 hours was 838.6 muM. The no observed effect concentration and predicted no effect concentration of camphor on D. magna, which was more sensitive than D. rerio, were calculated as 55.2 muM and 3.95 muM, respectively. Morphological abnormalities in D. rerio embryos exposed to camphor increased over time. Coagulation, delayed hatching, yolk sac edema, pericardial edema, and pigmentation of embryos mainly appeared between 24 and 48 hours. Further, symptoms of scoliosis and head edema occurred after 72 hours. In addition, bent tails, ocular defects and collapsed symptoms of fertilized embryonic tissue were observed after 96 hours. CONCLUSIONS: The camphor toxicity results suggest that continuous observations on the ecosystem are necessary to monitor toxicity in areas where biological pesticides containing camphor are sprayed.

Water quality assessment in piracicamirim creek upstream and downstream a sugar and ethanol industry through toxicity tests with cladocerans

An environmental impact study was conducted to determine the Piracicamirim's creek water quality in order to assess the influence of effluents from a sugar industry in this water body. For this, toxicity tests were performed with a water sample upstream and downstream the industry using the microcrustaceans Daphnia magna, Ceriodaphnia dubia and Ceriodaphnia silvestrii as test organisms, as well as physical and chemical analysis of water. Results showed that physical and chemical parameters did not change during the sampling period, except for the dissolved oxygen. No toxicity was observed for D. magna and reproduction of C. dubia and C. silvestrii in both sampling points. Thus, the industry was not negatively impacting the quality of this water body.

Simultaneous decolorization and detoxification of black reactive 5 using TiO2 deposited over borosilicate glass / Decoloración simultánea y la desintoxicación de reactivo negro 5 con TiO2 depositadas sobre el vidrio de borosilicato por la técnica de sedimentación / Descoloração simultânea e a desintoxicação do preto reativo 5 com TiO2 depositadas em vidro de borosilicato pela técnica de sedimentação

Objective. Removal and detoxification of azo dye by photocatalysis with TiO2. Materials and methods. TiO2 films were prepared by sedimentation at pH 1.3, using as support a borosilicate glass, annealed for 1 hour at 450 °C. Physical characterization was performed by Scanning Electron Microscopy, X-ray diffraction and UV/VIS spectrometry. Dye Black Reactive 5 removal was carried-out in a quartz photo-reactor. Results. Optical characterization revealed the films displayed evident TiO2 spherical particles of various irregular sizes, porous, and without fractures. The average crystal size was 77.5 nm and 77.7 nm for 50 °C (dried temperature) and 450 °C (annealed temperature) respectively. The energy of the band gap (GAP) was 3.02 and 2.68 eV respectively. Maximum concentration of dye that negatively affected color removal was 80 mg/L (17%). At lower dye's concentrations (10, 50 and 70mg/L) decolorization was greater than 80%. TiO2 films were reused for five consecutive cycles of 6 hours at 10 mg/L (>80%), and three cycles of 10 hours at 70 mg/L (> 80%). Toxicity results demonstrate that Daphnia magna was more sensitive than Lactuca sativa. Conclusion. TiO2 films obtained by sedimentation demonstrated a high reactive black 5 decolorization and COD removal (86% and 100%), as well as toxicity reduction.

Objetivo. Decolorización y disminución de la toxicidad de un azo colorante usando fotocatálisis con TiO2. Materiales y métodos. Las películas de TiO2 fueron crecidas por sedimentación a pH 1,3 empleando vidrio de borosilicato como sustrato. La caracterización física se realizó por medio de microscopía electrónica de barrido, difracción de rayos X y espectrometría de absorción UV/vis. Los estudios de remoción del colorante Negro Reactivo 5, se realizaron en un fotoreactor de cuarzo. Resultados. De acuerdo con la caracterización óptica, las películas de TiO2 presentaron partículas esféricas, con diferentes tamaños, irregulares y sin fracturas. El tamaño del cristal fue 77,5 nm y 77,7 nm para 50 y 450° C y la energía de banda prohibida fue 3,02 y 2,68 eV, respectivamente. La concentración máxima del colorante que afectó negativamente la remoción de color fue 80 mg/L (17%). A concentraciones más bajas de NR5 (10, 50 y 70 mg/L) la decoloración fue superior al 80%. Las películas de TiO2 se reutilizaron por 5 ciclos de 6 horas a 10 mg/L y 3 ciclos de 10 h a 70 mg/L. Los estudios de toxicidad en Lactuca sativa y Daphnia magna demostraron que D. magna fue más sensible que L. sativa. Conclusión. Las películas de TiO2 crecidas por sedimentación decoloraron el colorante negro reactivo 5 en un 86% y removieron la demanda química de oxígeno en un y 100%, igualmente redujeron la toxicidad.

Objetivo. Descolorar e diminuir a toxicidade de um corante azo utilizando fotocatálise com TiO2. Materiais e métodos. Os filmes de TiO2 foram obtidos por sedimentação a pH 1,3 usando vidro de borosilicato como substrato. A caracterização física foi realizada por microscopia eletrônica de varredura, difração de raios X e espectrometria de absorção UV/vis. Os estudos de remoção de corante Preto Reativo 5, foram realizados num fotorreator de quartzo. Resultados. De acordo com a caracterização óptica, os filmes de TiO2 presentearão partículas esféricas com tamanhos diferentes, irregulares e sem fracturas. O tamanho do cristal foi de 77,5 nm e 77,7 nm para 50 e 450°C e a energia de banda proibida foi 3,02 e 2,68 eV, respectivamente. A concentração máxima do corante que afetou negativamente a remoção de cor foi de 80 mg/L (17%), em concentrações mais baixas (70, 50 e 10 mg/L) a descoloração foi superior a 80%. Os filmes TiO2 foram reutilizados em 5 ciclos de 6 horas a 10 mg/L e 3 ciclos de 10 horas a 70 mg/L. Os estudos de toxicidade com Lactuca sativa e Hydra attenuata demonstraram que H. attenuata foi mais sensível que L. sativa. Conclusão. Os filmes de TiO2 obtidos por sedimentação descoloram o corante Preto Reativo 5 e removeram a demanda química de oxigénio em 86% e 100%, respectivamente; do mesmo modo reduziram a toxicidade.

Toxicity Assessment of Titanium (IV) Oxide Nanoparticles Using Daphnia magna (Water Flea)

OBJECTIVES: Titanium dioxide (TiO2), a common nanoparticle widely used in industrial production, is one of nano-sized materials. The purpose of this study was to determine the acute and chronic toxicity of TiO2 using different size and various concentrations on Daphnia magna. METHODS: In the acute toxicity test, four concentrations (0, 0.5, 4, and 8 mM) for TiO2 with 250 or 500 nm and five concentrations (0, 0.25, 0.5, 0.75, and 1 mM) for TiO2 with 21 nm were selected to analyze the toxic effect to three groups of ten daphnia neonates over 96 hours. In addition, to better understand their toxicity, chronic toxicity was examined over 21 days using 0, 1, and 10 mM for each type of TiO2. RESULTS: Our results showed that all organisms died before the reproduction time at a concentration of 10 mM of TiO2. In addition, the exposure of anatase (21 nm) particles were more toxic to D. magna, comparing with that of anatase (250 nm) and rutile (500 nm) particles. CONCLUSIONS: This study indicated that TiO2 had adverse impacts on the survival, growth and reproduction of D. magna after the 21days exposure. In addition, the number of test organisms that were able to reproduce neonates gradually were reduced as the size of TiO2 tested was decreased.

Evaluación del crecimiento de un cultivo de Daphnia magnaalimentado con Saccharomyces cereviseae y unenriquecimiento con avena soya / Avaliação do crescimento de um cultivo de Daphnia magna alimentada conSaccharomyces cereviseae e um meio enrriquecido com aveia soja / Growth culture evaluation of Daphnia magna feed with Saccharomyces cereviseae enrichment with oat soy

Se realizó el cultivo experimental de cladócero Daphnia magna alimentado con probióticos. Serealizaron 16 ensayos experimentales, en el laboratorio de larvicultura de peces y alimento vivo (Larpeali)de la Facultad de Ciencias Agrarias de la Universidad de Antioquia, bajo condiciones controladas detemperatura ambiente (21 - 25 °C), temperatura del agua (22 - 23 °C) y pH (7.6). Empleando una dietade Saccharomyces cereviseae y un medio de enriquecimiento con ácidos grasos (n-6) proveniente deharina avena-soya. Las concentraciones de dieta y enriquecimiento fueron de 25 ppm y 12.5 ppm, enarreglo factorial 2x2 (2 niveles de dieta con levadura y 2 niveles dieta con avena de soya), los cultivosde Daphnia por tratamiento se realizaron con cuatro replicas con el fin de determinar su efecto sobreel desempeño de la población. Se alimentaron cada tercer día, durante 15 días, evaluándose el númerode organismos al final del período. Se obtuvieron diferencias altamente significativas (p<0.01) para elefecto del tratamiento con una concentración de 25 ppm Saccharomyces cereviseae + harina de avenasoyaa una concentración de 25 ppm. De igual forma se observó una diferencia significativa (p<0.05) en el tratamiento con Saccharomyces cereviseae a 12.5 ppm + harina de avena-soya 25 ppm sobre elcrecimiento poblacional de los cladóceros. En el resto de los tratamientos no se observaron diferenciassignificativas (p>0.05). Se evidenció que la combinación de estos componentes en sus concentracionesmás altas potenció el crecimiento de la Daphnia magna, alcanzando un número de microcrustáceos de826ª Daphnias/L ± 9.57. Se puede concluir que los cladóceros por sus características de crecimiento encultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasa útilcomo alimento vivo en acuicultura.

Experimental cultivate cladocerans Daphnia magna feed with probiotics was realized. At Universityof Antioquia, Faculty of Agrarian Science, Larviculture, fish and food live Laboratory (Larpeali), undercontrolled conditions of environmental temperature between (21 - 25 °C), water temperature (22 - 23°C)and pH (7.6), were performed. One diet of Saccharomyces cereviseae was used and one enriched mediumof oat-soy flour (fatty acid, n-6) to concentrations of diet and enriched medium were the same, 25 ppmand 12.5 ppm, 2x2 factorial treatment arrangements (2 levels of Saccharomyces cereviseae and 2 levelsof oat-soy flour, diets was fed to four replicates of Daphnia culture per treatment in order to determinetheir effects on the populations cultivated. A 15-days feeding, each third day, trial were conducted, to assessthe organisms at final period. The results showed significant high difference (p<0.01) for the effect of thetreatment with Saccharomyces cereviseae 25 ppm + oat-soy flour 25 ppm. In the same way, the results showedsignificant difference (p<0.05) for the effect of the treatment with Saccharomyces cereviseae 12.5 ppm +oat-soy flour 25 ppm on the population growth of the cladocerans. Rest of treatments were not significantlydifference (p>0.05). The results showed that the combination of their high concentrations of componentsenhanced the population growth of Daphnia magna, reaching a number of microcrustaceans of 826ª ± 9.57.These cladocerans for their characteristics of growth in culture, present favorable adaptation to the handlingconditions to produce biomasses potentially useful as nutritious particle as live food in aquaculture purposes.

O objetivo do experimento foi avaliar o efeito das gorduras saturadas e insaturadas e seu grau deproteção (protegidas e sem proteção) sob a cinética e a extensão da degradação in vitro da matéria seca(MS) em dietas para ruminantes. Quatro dietas foram formuladas para conter o mesmo nível de energia(3200 Kcal ED /Kg MS) e proteína (13%PC) a ração total misturada (RTM), de acordo com as necessidadesnutricionais de ovelhas em fase de finalização, quatro tipos de gorduras foram feitas com 8% de MS eforam testados tipos de gorduras foram testados: 1) gordura saturada sem proteção (GSSP), 2) gordurasaturada protegida (GSP), 3) gordura insaturada sem proteção (GISP) e 4) gordura insaturada protegida(GIP). Para estimar a cinética e a extensão da degradação da MS e cinética da produção de gás, as raçõesforam avaliadas mediante a técnica in vitro de produção de gás, seguindo os modelos propostos por Orskove McDonald (1979) y France et al (1993), para isto foi empregado o procedimento PROC NLIN de SAS(2001). Ao mesmo tempo, foi realizado um analise de medidas repetidas no tempo para verificar o efeito dostratamentos sobre a produção de gás e a degradação da MS no tempo com ajuda do procedimento PROCMIXED do SAS (2001.) Neste experimento verificou-se que a utilização de gorduras insaturadas protegidasnão afetou a degradação de MS quando comparadas com as não protegidas. No caso das gorduras saturadas,não houve um claro efeito da proteção sob a degradação e a cinética de fermentação da MS.

Larvicidal activity of the water extract of Moringa oleifera seeds against Aedes aegypti and its toxicity upon laboratory animals

In this work, biological effects of the water extract of Moringa oleifera seeds (WEMOS) were assessed on eggs and 3rd instar larvae of Aedes aegypti and on its toxicity upon laboratory animals (Daphnia magna, mice and rats). Crude WEMOS showed a LC50 value of 1260µg/mL, causing 99.2 ± 2.9 percent larvae mortality within 24 h at 5200µg/mL, though this larvicidal activity has been lost completely at 80ºC/10 min. WEMOS did not demonstrate capacity to prevent egg hatching. After extensive dialyses of the crude WEMOS into watersoluble dialyzable (DF) and nondyalizable (NDF) fractions, only DF maintained its efficacy to kill larvae. Acute toxicity evaluations on daphnids (EC50 of 188.7µg/mL) and mice (LD50 of 446.5 mg/kg body weight) pointed out to low toxicity. Despite the thymus hypertrophy, WEMOS revealed to be harmless in orally and subacutelytreated rats. In conclusion, WEMOS has thermostable bioactive compounds against Ae. aegypti larvae with apparent molecular mass lower than 12 kDa and moderately toxic potential.

Neste trabalho, o extrato aquoso das sementes de Moringaoleifera (EASMO) foi avaliado quanto aos seus efeitos biológicos sobre ovos e larvas de Aedes aegypti no 3ºestágio de desenvolvimento e sua toxicidade sobre animais de laboratório(Daphnia magna, camundongos e ratos). O EASMO bruto revelou uma CL50 de 1.260 µg/mL, causando 99, 2 ± 2, 9 por cento de mortalidade em 24 h na concentração de 5.200 µg/mL, embora o mesmo não tenha sido capaz de impedir a eclosão dos ovos. A atividade larvicida extinguiu-se após aquecimento do extrato a 80ºC/10 min. Diálises sucessivas do EASMO bruto resultaram em duas frações solúveis em água (Fração dializável, FD; Fração nãodializável, FND), dentre as quais apenas a FD mostrou ação larvicida. Testes de toxicidade aguda realizadosem dáfnias (CE50 de 188, 7 µg/mL) e camundongos (DL50 de446,5 mg/kg de peso corpóreo) evidenciaram baixa toxicidade. Apesar da hipertrofia tímica, o EASMO mostrou ser atóxicoapós tratamento subagudo via oral em ratos. Conclui-se, portanto, que o EASMO apresenta substâncias com capacida de larvicida contra Ae. aegypti, as quais possuem massa molecular aparente menor que 12 kDa e potencial tóxico moderado.

Accumulation of chromium and interaction with other elements in Chlorella vulgaris (Cloroficeae) and Daphnia magna (Crustacea, Cladocera).

Assays with Chlorella vulgaris Beijerinck Novakova, 1890 and Daphnia magna Straus, 1820 were performed to determine Cr and other elements concentration in tissues of both species by instrumental neutron activation analysis (INAA), after being exposed to 150, 280 and 350 .g l-1Cr (VI). Interaction among Cu, Zn, Fe and Cr were also registered. In the control of C. vulgaris, the amount of Cr was < 4μg g-1; in the treatments with Cr (VI) the values were 47, 82 and 100 folds greater than the control for the lowest, intermediate and highest concentrations tested respectively. In the control of D. magna, the amount of Cr was <3 μg g-1; in the treatments with Cr (VI) the values were 14, 13 and 27 folds higher than the control for the lower, intermediate and higher Cr (VI) concentrations respectively, and from 3 to 9 times less than for C. vulgaris These results show that C. vulgaris is very efficient accumulator of Cr (VI) from polluted waters, and in consequence, it is proposed to be used in phytoremediation procedures.

Bioensayos de toxicidad aguda utilizando Daphnia magna Straus (Cladocera, Daphniidae) desarrollada en medio de cultivo modificado

Daphnia magna es utilizada como bioindicador ambiental de efluentes dulciacuícolas en ensayos ecotoxicológicos, sin embargo los sistemas de cultivo tradicionales pueden resultar costosos, por lo cual se ha desarrollado un nuevo medio de cultivo. Se aislaron 10 cepas de D. magna, se evaluó el desarrollo de la población (Conteo total de individuos y de hembras grávidas) empleando 3 medios de cultivo, medio A: jugo de alfalfa (0,250 gr/mL), medio B: levadura fresca disuelta y medio C: jugo de alfalfa y levadura disuelta. De las 10 cepas, 4 desarrollaron satisfactoriamente en el medio A, pero no sobrevivieron en los otros medios. En los ensayos ecotoxicológicos agudos frente a dicromato de potasio se encontraron valores promedio de EC50-24h 0,4045 mg/L ± 0,0389 y EC50-48h 0,1857 mg/L ± 0,0072. Con estas 4 cepas se realizaron ensayos ecotoxicológicos agudos para cianuro de potasio, que es un contaminante del sector minero, encontrándose valores de EC50-24h 1,5388 mg/L ± 0,1146 y EC50-48h de 0,6359 mg/L ± 0,0516. Los valores de EC50 a las 48 horas están por debajo del límite permisible para liberación de cianuro en efluentes del sector Energía y Minas.

Daphnia magna is a test organism used in ecotoxicological assays of freshwater; however, traditional culture systems for this organism could result expensive, for that the aim of this research was to developed a new economic culture medium. With this purpose, 10 strains of D. magna were isolated, their population development was evaluated by total count of organisms and pregnant females using 3 different culture media: (A) alfalfa juice, (B) solved yeast and (C) a mixture of alfalfa juice plus solved yeast. Successful development of 4 strains was observed in the A medium, but the same strains failed to survive in the B and the C media. The 24h and 48h EC50 average values in acute ecotoxicological assays with potassium dicromate were 0,4045 mg/L ± 0,0389 and 0,1857 mg/L ± 0,0072 respectively. Also, acute ecotoxicological assays with these 4 strains were performed using potassium cyanide, which is a toxic reactive frequently used in mining operations. In this case 24h EC50 value was 1,5388 mg/L ± 0,1146 and 48h EC50 values were 0,6359 mg/L ± 0,0516. 48h EC50 values were lower than the cyanide permissible effluent values established by the Energy and Mining Authority.