Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Toxins (Basel) ; 16(1)2024 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-38251262

RESUMO

Deoxynivalenol (DON) is a predisposing factor for necrotic enteritis. This study aimed to investigate the effects of a DON and Clostridium perfringens (CP) challenge on the intestinal morphology, morphometry, oxidative stress, and immune response of broilers. Additionally, we evaluated the potential of a Lactobacillus spp. mixture as an approach to mitigate the damage induced by the challenge. One-day-old broiler chickens (n = 252) were divided into seven treatment groups: Control, DON, CP, CP + DON, VL (DON + CP + viable Lactobacillus spp. mixture), HIL (DON + CP + heat-inactivated Lactobacillus spp. mixture), and LCS (DON + CP + Lactobacillus spp. mixture culture supernatant). Macroscopic evaluation of the intestines revealed that the CP + DON group exhibited the highest lesion score, while the VL and HIL groups showed the lowest scores. Microscopically, all Lactobacillus spp. treatments mitigated the morphological changes induced by the challenge. DON increased levels of reactive oxygen species (ROS) in the jejunum, and CP increased ROS levels in the jejunum and ileum. Notably, the Lactobacillus spp. treatments did not improve the antioxidant defense against CP-induced oxidative stress. In summary, a Lactobacillus spp. mixture, whether used as a probiotic, paraprobiotic, or postbiotic, exerted a partially protective effect in mitigating most of the intestinal damage induced by DON and CP challenges.


Assuntos
Galinhas , Probióticos , Tricotecenos , Animais , Clostridium perfringens , Espécies Reativas de Oxigênio , Intestinos , Lactobacillus , Probióticos/farmacologia
2.
Animals (Basel) ; 13(19)2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37835616

RESUMO

(1) Background: This study's objective was to determine whether adding vegetable biocholine (VB) to pigs' diets would minimize the negative effects caused by daily aflatoxin (B1 + B2) intake. (2) Methods: We used seventy-two whole male pigs weaned at an average of 26 days and divided them into four groups with six replicates each (2 × 2 factorial). The treatments were identified as Afla0VB0 (negative control, without aflatoxin and without VB); Afla500VB0 (positive control, 500 µg/kg of aflatoxins; Afla0VB800 (800 mg/kg of VB); and Afla500VB800 (500 µg/kg of aflatoxin +800 mg/kg of VB). (3) Results: In the first 20 days of the experiment, only the pigs from Afla500VB0 had less weight gain and less feed consumption, different from the 30th to 40th day, when all treatments had lower performance than the negative control. In the liver, higher levels of oxygen-reactive species and lipid peroxidation were observed in Afla500VB0, associated with greater activity of the enzymes alanine aminotransferase and aspartate aminotransferase. In the jejunum, oxidative stress was associated with nitrous stress in Afla500VB0. An increase in splenic glutathione S-transferase activity in the Afla500VB800 animals was observed. (4) Conclusions: Consuming a diet contaminated with 500 µg/kg of aflatoxin influences the health and performance in the nursing phase in a silent way; however, it generates high economic losses for producers. When VB was added to the pigs' diet in the face of an aflatoxin challenge, it showed hepatoprotective potential.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31493584

RESUMO

Aflatoxin B1 (AFB1) is one of the most important mycotoxins due to its hepatotoxic and carcinogenic effects on animals. The effect of dietary supplementation with vegetable choline (VC) at 400, 800, and 1200 mg/kg against the deleterious effects of AFB1 (2 ppm/kg diet) in the liver of Nile tilapia (Oreochromis niloticus) was studied. The experimental period was 81 days, and the diet with VC was offered to the fish for 60 days prior to challenge with AFB1. Diets with AFB1 were tested in three replications and animals were analyzed at days 14 and 21 of dietary intake. The addition of VC to tilapia diet increased body weight (days 30 and 60 pre-challenge and day 21 post-challenge). The group fed aflatoxin-contaminated diet presented significantly reduced antioxidant enzymes and increased reactive oxygen species (ROS) levels, thiobarbituric acid reactive species (TBARS) levels, and protein carbonyl (PC) content in the liver. Dietary supplementation with VC at 800 and 1200 mg/kg demonstrated a significant protective effect, avoiding the increase of ROS, TBARS, and PC levels in the liver of tilapia from the aflatoxin contaminated groups. Thus, dietary VC supplementation may be used in tilapia to increase antioxidant status and reduce the negative effects caused by AFB1 toxicity. Based on the findings, it is recommended to use VC as a food supplement for Nile tilapia in order to avoid AFB1 toxication. In addition, decreased aflatoxin toxicity can be attributed to the VC antioxidant property.


Assuntos
Aflatoxina B1/toxicidade , Ração Animal/análise , Colina/farmacologia , Ciclídeos , Doenças dos Peixes/induzido quimicamente , Contaminação de Alimentos , Aflatoxina B1/administração & dosagem , Animais , Catalase/genética , Catalase/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Doença Hepática Induzida por Substâncias e Drogas/veterinária , Colina/administração & dosagem , Dieta/veterinária , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Doenças dos Peixes/tratamento farmacológico , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo
5.
Ciênc. rural (Online) ; 50(6): e20190779, 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1133266

RESUMO

ABSTRACT: Essential oils are possible alternatives to the use of synthetic pesticides for control of fungal contamination. Ginger (Zingiber officinale) essential oil (GEO) is known for having antifungal and antiaflatoxigenic properties, but its use as a fumigant in situ has not been studied yet. The aim of this study was to evaluate GEO's effects upon Aspergillus flavus as a fumigant agent in stored maize grains. The main compounds reported in GEO were α-zingiberene (23.85%) and geranial (14.16%), characterized by gas chromatography-mass spectrometry and nuclear magnetic resonance. The GEO was used as a fumigant in irradiated maize grains in concentrations ranging from 5 to 50 µg/g and the resulting effects were compared to a synthetic antifungal agent (carbendazim and thiram), an antifungal traditionally used for seed treatment. The antifungal efficacy of GEO against A. flavus has been proven in a dose-dependent manner through in situ (maize grains) test. The GEO inhibited aflatoxin production at concentrations 25 and 50 µg/g and controlled fungal growth. Therefore, GEO can be used as an effective and non-toxic alternative to conventional treatments in stored maize grains for the natural control of A. flavus.


RESUMO: Os óleos essenciais são possíveis alternativas ao uso de praguicidas sintéticos no controle da contaminação por fungos. O óleo essencial de gengibre (Zingiber officinale - OEG) é conhecido por possuir propriedades antifúngicas e antiaflatoxigênicas, mas seu uso como fumigante in situ ainda não foi estudado. O objetivo deste estudo foi avaliar os efeitos do OEG sobre Aspergillus flavus como agente fumigante em grãos de milho armazenados. Os principais compostos encontrados no OEG foram α-zingibereno (23,85%) e geranial (14,16%), caracterizados por cromatografia gasosa acoplada a espectrometria de massas e ressonância magnética nuclear. O OEG foi utilizado como fumigante em grãos de milho irradiados em concentrações variando de 5 a 50 µg/g e os efeitos resultantes foram comparados a um agente antifúngico sintético (carbendazim e tiram), antifúngico tradicionalmente usado para o tratamento de sementes. A eficácia antifúngica do OEG contra A. flavus foi comprovada de maneira dependente da dose através do teste in situ (grãos de milho). O OEG inibiu a produção de aflatoxina nas concentrações 25 e 50 µg/g e controlou o crescimento de fungos. Portanto, o OEG pode ser usado como uma alternativa eficaz e não tóxica aos tratamentos convencionais em grãos de milho armazenados para o controle natural de A. flavus.

6.
Int J Food Microbiol ; 286: 128-138, 2018 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-30099281

RESUMO

Effective and environmentally-friendly alternatives to traditional disinfectants are necessary to reduce the pollution and the emergence of antimicrobial-resistant bacterial strains in food-related environments. In the present study, treatments based in single and combined applications of plant essential oils (EOs) were evaluated for control Staphylococcus aureus biofilms. EOs of Lippia sidoides, Thymus vulgaris and Pimenta pseudochariophyllus showed a higher efficacy than peracetic acid and sodium hypochlorite against S. aureus planktonic cells and 24-h-old biofilms formed on polystyrene and stainless steel under food-related conditions. High concentrations of thymol and chavibetol were detected in these EOs, as well as the presence of other antimicrobial compounds such as carvacrol, eugenol, p-cymene, limonene, α-pinene, α-terpineol, terpinen-4-oil and linalool. L. sidoides oil were particularly effective against S. aureus, but doses higher than 2.75% (v/v) were required to completely eradicate 24-h-old biofilms. Binary combinations of L. sidoides, T. vulgaris and P. pseudochariophyllus allowed decrease significantly doses required to reduce 99.99% the number of biofilm cells. Furthermore, peracetic acid increased its efficacy against S. aureus biofilms by the combined application with these EOs. The most effective treatments against S. aureus biofilms were those combining L. sidoides with T. vulgaris or peracetic acid. Therefore, these EO-based treatments can be considered as an effective and environmentally-friendly alternative to control S. aureus biofilms in food-contact surfaces.


Assuntos
Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Desinfetantes/farmacologia , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Monoterpenos Acíclicos , Monoterpenos Bicíclicos , Biofilmes/efeitos dos fármacos , Monoterpenos Cicloexânicos , Cicloexenos/farmacologia , Cimenos , Limoneno/farmacologia , Testes de Sensibilidade Microbiana , Monoterpenos/farmacologia , Ácido Peracético/farmacologia , Hipoclorito de Sódio/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Timol/farmacologia , Thymus (Planta)/química
7.
Food Addit Contam Part B Surveill ; 11(4): 273-280, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30035664

RESUMO

Few studies have addressed the distribution of mycotoxins in soybean and/or their processing fractions. In this study, samples from commercial lots were collected in four Brazilian states. The distribution of mycotoxins in soybean fractions, according to their commercial grading system, namely whole kernels (WK), split, broken and crushed kernels (SBCK), damaged kernels (DK), heat damaged and burned kernels (HDBK), moldy kernels (MK), greenish kernels (GK), foreign material + impurities (FMI), were analyzed using HPLC-FLD. AFB1 and ZEN tested positive in 43.3 and 80%, respectively. The incidence of AFB1 was higher in MK (50%), followed by HDBK (30.4%) and FMI (26.0%). ZEA incidence ranged from 69% (SBCK) to 100% (HDBK). Co-occurrence (53.3%) in at least one fraction was also detected. Brazil is the second world producer of soybeans, which places the country in a very important position. Therefore, the information provided is crucial and timely relevant for the industry and policymakers.


Assuntos
Aflatoxina B1/análise , Contaminação de Alimentos/análise , Glycine max/química , Sementes/química , Zearalenona/análise , Brasil , Cromatografia Líquida de Alta Pressão , Humanos
8.
Microb Pathog ; 117: 259-264, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29471136

RESUMO

Mycotoxins are responsible for economic losses in the swine production industry, especially during post-weaning, when piglets are physiologically immature. Spray-dried porcine plasma (SDPP), added to pig diets, may help reduce losses due to mycotoxins. This work investigates the effects of SDPP in post-weaning piglets fed with diets containing natural contaminants or with more contaminants (co-contamination by mycotoxins). Fifty-six castrated weaned piglets were used in a randomized 2 (0 and 6% of SDPP) x 2 (natural contamination or co-contamination with mycotoxin) factorial design, with seven experimental units of two piglets each. The natural contaminants were 0.95 µg/kg aflatoxins +450 µg/kg fumonisins. The co-contaminated diet contained 300 µg/kg aflatoxins +8000 µg/kg fumonisins. Animals were fed 15 days with experimental diets. Feed intake, weight gain, feed efficiency, diarrhea incidence, and economic feasibility of SDPP treatement were evaluated in three periods of five days each. There was no interaction (P < 0.05) between mycotoxins levels and SDPP. Feed intake, weight gain and feed efficiency were higher (P < 0.05) in diets supplemented with SDPP. Animals fed with SDPP showed lower (P < 0.05) diarrhea incidence in the 1-10 day and 1-15 day periods. The experimental dose of mycotoxins reduced (P < 0.05) weight gain at 11-15 days. SDPP proved to be economical feasible over the total experimental period (1-15 days). Spray-dried plasma improved weight gain, feed intake and reduced diarrhea incidence in piglets post-weaning, but did not correlate with various levels of mycotoxins.


Assuntos
Ração Animal , Proteínas Sanguíneas/uso terapêutico , Diarreia/prevenção & controle , Suplementos Nutricionais , Micotoxinas/toxicidade , Suínos/crescimento & desenvolvimento , Desmame , Aumento de Peso , Aflatoxinas/efeitos adversos , Aflatoxinas/toxicidade , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Custos e Análise de Custo , Dieta/veterinária , Modelos Animais de Doenças , Contaminação de Alimentos , Fungos/metabolismo , Incidência , Masculino , Plasma , Suínos/sangue , Suínos/fisiologia , Fatores de Tempo
9.
Bol. latinoam. Caribe plantas med. aromát ; 15(4): 215-232, jul. 2016. tab
Artigo em Inglês | LILACS | ID: biblio-907539

RESUMO

To investigate potential sources of novel grain protector compounds against Sitophilus zeamais (Coleoptera: Curculionidae), which is an important insect pest of stored cereals, this study evaluated the bioactivity of ethanolic extracts (66) prepared from 29 species belonging to 11 different genera of Neotropical Annonaceae. A screening assay demonstrated that the most pronounced bioactive effects on S. zeamais were caused by ethanolic extracts from Annona montana, A. mucosa, A. muricata, and A. sylvatica seeds, causing the death of all weevils exposed, almost complete inhibition of the F1 progeny and a drastic reduction in grain losses. Furthermore, the ethanolic extracts obtained from the leaves of A. montana, A. mucosa, A. muricata, and Duguetia lanceolata, especially A. montana and A. mucosa, demonstrated significant bioactive effects on the studied variables; however, the activity levels were less pronounced than in the seed extracts, and the response was dependent on the concentration used. This study is the first to report the activity of secondary metabolites from D. lanceolata on insects as well as the action of A. sylvatica on pests associated with stored grains.


Para investigar las posibles fuentes de nuevos compuestos protectores de granos contra Sitophilus zeamais (Coleoptera: Curculionidae), una importante plaga de los cereales almacenados, este estudio evaluó la bioactividad de los extractos etanólicos (66) preparados a partir de 29 especies pertenecientes a 11 géneros distintos de Anonaceas Neotropicales. Un ensayo de selección demostró que los efectos bioactivos más relevantes sobre S. zeamais fueron causados por los extractos etanólicos de las semillas de Annona montana, de A. mucosa, de A. muricata y de A. sylvatica, que causaron la muerte de todos los gorgojos expuestos, la inhibición parcial de la progenie F1 y una drástica reducción de las pérdidas de grano. Además, los extractos etanólicos obtenidos de las hojas de A. montana, de A. mucosa, de A. muricata y de Duguetia lanceolata, especialmente de A. montana y de A. mucosa, demostraron efectos bioactivos significativos sobre las variables estudiadas. Sin embargo, los niveles de bioactividad fueron menores en comparación con los extractos de semillas, y la respuesta fue dependiente de la concentración utilizada. Este estudio es el primer relato sobre la actividad de los metabolitos secundarios de D. lanceolata sobre insectos, así como la acción de A. sylvatica sobre plagas asociadas a los granos almacenados.


Assuntos
Animais , Annonaceae/química , Repelentes de Insetos/análise , Inseticidas/análise , Extratos Vegetais/química , Gorgulhos , Grão Comestível , Armazenamento de Alimentos , Controle de Insetos
10.
Food Addit Contam Part B Surveill ; 9(2): 142-51, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26886061

RESUMO

Fusarium mycotoxins deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) were investigated in wheat from the 2009 and 2010 crop years. Samples (n = 745) from commercial fields were collected in four wheat producing regions (WPR) which differed in weather conditions. Analyses were performed using HPLC-DAD. Contamination with ZEN, DON and NIV occurred in 56, 86 and 50%, respectively. Also, mean concentrations were different: DON = 1046 µg kg(-1), NIV < 100 µg kg(-1) and ZEN = 82 µg kg(-1). Co-occurrence of ZEN, DON and NIV was observed in 74% of the samples from 2009 and in 12% from 2010. Wet/cold region WPR I had the highest mycotoxin concentration. Wet/moderately hot region WPR II had the lowest mycotoxin levels. Furthermore, the mean concentration of each mycotoxin was higher in samples from 2009 as compared with those from 2010. Precipitation during flowering or harvest periods may explain these results.


Assuntos
Grão Comestível/química , Contaminação de Alimentos/análise , Fusarium , Tricotecenos/análise , Triticum/química , Zearalenona/análise , Brasil , Cromatografia Líquida de Alta Pressão , Clima , Dieta , Humanos , Tempo (Meteorologia)
11.
Arq. Inst. Biol ; 83: e0072014, 2016. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-1006438

RESUMO

O desenvolvimento de pesticidas é uma constante no setor agropecuário, visando oferecer produtos menos agressivos ao meio ambiente e novos princípios ativos, evitando o aparecimento de resistência. O estudo de alternativas aos fungicidas utilizados no tratamento de sementes tem nos óleos essenciais um campo para prospecção. Esta pesquisa teve como objetivo avaliar os efeitos dos óleos essenciais provenientes de folhas de C. citriodora e E. camaldulensis , em sementes de milho da variedade AL Bandeirante, de diferentes localidades. A qualidade fisiológica e sanitária das sementes foi avaliada quando se trataram as amostras utilizando os óleos individualmente, a mistura equitativa desses óleos e o tratamento com um antifúngico comercial. Foi observado que o tratamento com os óleos C. citriodora e E. camaldulensis e a mistura dos óleos não afetou a germinação imediata das sementes de Avaré. No lote de Bernardino de Campos, o tratamento com C. citriodora foi prejudicial; com o E. camualdulensis , apesar de não diferenciar estatisticamente dos demais, diminuiu a germinação, o que impediria sua utilização como semente, segundo o padrão normatizado (de 85%) pelo Ministério da Agricultura, Pecuária e Abastecimento (MAPA). O óleo de E. camaldulensis apresentou efeito fitotóxico, diminuindo o comprimento das plântulas; a acetona utilizada como solvente não influenciou sobre a germinação, mas apresentou efeito fitotóxico após o envelhecimento acelerado. A aplicação dos óleos isoladamente foi capaz de diminuir a incidência dos fungos dos gêneros Penicillium e Fusarium , mas para Aspergillus o comportamento foi semelhante ao antifúngico comercial, não apresentando efeito quando comparado ao tratamento testemunha.(AU)


The development of pesticides is a constant in the agricultural sector in order to offer products less aggressive to the environment and new active ingredients, preventing the emergence of resistance. The alternative study to fungicides used for seed treatment has the essential oils field for prospecting. This research aimed to evaluate the effects of essential oils from leaves of C. citriodora and E. camaldulensis in maize seed variety AL Bandeirante, from different locations. The physiological and sanitary quality of the seeds were evaluated when treated samples using the oils individually, equal mixture of these oils and treatment with a commercial antifungal. It was observed that the treatment with the oils C. citriodora , E. camaldulensis and the mixture of oils did not affect the immediate germination of seeds Avare. In the batch Bernardino de Campos, treatment with C. citriodora was harmful and E. camualdulensis , although not statistically differ from the others, decreased germination which would prevent its use as seed, according to the standard regulated by the Ministry of Agriculture, Livestock and Supply (MAPA), 85%. The E. camaldulensis oil showed phytotoxic effect decreasing the length of seedlings, acetone used as a solvent had no effect on germination but showed phytotoxic effect after accelerated aging. The application of oils alone was able to reduce the incidence of fungi of the genus Penicillium and Fusarium, Aspergillus but the behavior was similar to commercial antifungal, showing no effect when compared to the control treatment.(AU)


Assuntos
Sementes , Óleos Voláteis , Eucalyptus rostrata , Zea mays , Antifúngicos , Agroindústria
12.
Artigo em Inglês | MEDLINE | ID: mdl-26001270

RESUMO

A total of 635 raw milk samples from 45 dairy farms, from three regions of São Paulo state - Brazil, were evaluated during 15 months for aflatoxin M1 (AFM1). AFM1 was determined by high performance liquid chromatograph with fluorescence detection. AFM1 was detected (>0.003 µg kg(-1)) in 72.9%, 56.3% and 27.5% of the samples from Bauru, Araçatuba and Vale do Paraíba regions, respectively. The mean AFM1 contamination considering all the samples was 0.021 µg kg(-1). Furthermore, the concentration of AFM1 was quite different among Bauru (0.038 µg kg(-1)), Araçatuba (0.017 µg kg(-1)) and Vale do Paraíba (<0.01 µg kg(-1)) regions. Only three samples (0.5%) had higher contamination than the tolerated limit in Brazil (0.50 µg kg(-1)) and 64 samples (10.1%) had a higher contamination than the maximum limit as set by the European Union (0.050 µg kg(-1)). The estimated AFM1 daily intake was 0.358 and 0.120 ng kg(-1) body weight per day for children and adults, respectively.


Assuntos
Aflatoxina M1/análise , Carcinógenos Ambientais/análise , Contaminação de Alimentos , Leite/química , Adulto , Aflatoxina M1/toxicidade , Animais , Brasil , Carcinógenos Ambientais/toxicidade , Criança , Cromatografia Líquida de Alta Pressão , Indústria de Laticínios , União Europeia , Inspeção de Alimentos , Guias como Assunto , Humanos , Limite de Detecção , Leite/efeitos adversos , Leite/normas , Reprodutibilidade dos Testes , Análise Espaço-Temporal , Espectrometria de Fluorescência
13.
Braz. j. microbiol ; 33(3): 250-254, July-Sept. 2002. tab
Artigo em Inglês | LILACS | ID: lil-349778

RESUMO

The aflatoxin distribution in corn fractions obtained after visual segregation for defects in 30 samples, known to be contaminated, was studied. Each sample was passed through a 5.0 mm round holes sieve, graded for defects and then segregated in sound kernels (regular kernels) and non-sound kernels (injured, germinated, fermented, moldy, heated, insect damaged, immature, broken, hollow, fermented up to », discolored, extraneous materials, and injured by other causes), as defined by the Brazilian Official Grading rules for corn. The non-sound kernels showed the highest contamination levels in all samples. The contamination levels of non-sound kernels (20 percent of total weight) ranged from 23 to 1,365 æg/kg of aflatoxins (B1, B2, G1 and G2) and were higher than sound kernels (p<1 percent) ranging from not detected (ND) to 126 æg/kg and in 87 percent of these the aflatoxin contents were lower than 20 æg/kg. Statistically significant correlation indexes were found among the percentage of defective groups like fermented, heated and sprouted kernels or the total injured kernels, and the estimated contamination levels for the sound and non sound fractions. It was concluded that the non-sound kernels fraction, even being small in weight, has contributed with 84 percent of the estimated contamination of the samples. The segregation of the non-sound kernels would favor a reduction in the contamination of corn lots. The poorer quality corn types (types 3 and Bellow Standart) have predominated among samples of the experiment


Assuntos
Aflatoxinas , Técnicas In Vitro , Zea mays , Poluição Ambiental , Métodos , Estudos de Amostragem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA