Estudo da percolação e estabilidade de taludes de pequenas barragens rurais compactadas em três diferentes umidades

This paper presents the study of stability and percolation of two dams sections with 5 m high, one composed by horizontal sand filter, and the other by a rockfill drain localized at the toe of the downstream slope. The stability analyzes were performed using Slope / W software, using the Simplified Bishop Method (1955), while the percolation analyses were performed by Seep / W software based on the theory of finite elements. In order to obtain the necessary parameters were conducted laboratory tests using disturbed and undisturbed soil samples collected at the Faculty of Agricultural Engineering at Unicamp. The samples used for shear strength determination and permeability tests were compacted at optimum moisture content and in 4% moisture deviation from this value in order to verify the influence of compaction moisture content on variation of slopes safety factors. The performed stability analyses demonstrated the variation of the safety factors depending of compaction moisture content, geometrical characteristics and type of drainage element. It was also observed that the flow in the analyzed sections occurs predominantly in foundation.2321119Este trabalho apresenta o estudo da estabilidade e percolação de duas seções de barragens com 5 m de altura, uma composta por filtro horizontal, e outra por dreno de enrocamento no pé do talude de jusante. As análises de estabilidade foram realizadas com uso do programa computacional Slope/W empregando-se o Método de Bishop Simplificado (1955), enquanto que as análises de percolação foram efetuadas pelo programa computacional Seep/W, baseado na teoria dos elementos finitos. Para a obtenção dos parâmetros foram conduzidos ensaios laboratoriais em amostras deformadas e indeformadas coletadas na Faculdade de Engenharia Agrícola da Unicamp. Os corpos de prova utilizados nos ensaios de resistência e permeabilidade foram compactados na umidade ótima e com desvios de umidade de 4% em relação a este valor no intuito de se verificar a influência da umidade de compactação na variação dos coeficientes de segurança de taludes. De acordo com as análises de estabilidade efetuadas pôde-se verificar que as seções estudadas apresentaram variação nos fatores de segurança em função do teor de umidade, de aspectos geométricos e tipo de elemento de drenagem. Também se concluiu que o fluxo nas seções analisadas ocorrerá predominantemente na fundação

Consumption of animal products and frauds: DNA-based methods for the investigation of authenticity and traceability in dairy and meat-derived products – a review

O aumento do poder de compra da população, especialmente em países emergentes como o Brasil, foi seguido pelo crescente consumo de carnes, leites e seus derivados, assim como pela maior exigência por padrões de qualidade destes produtos. Os diferentes tipos de fraude podem comprometer a qualidade e ferir os direitos do consumidor, sendo relevante a aplicação de métodos mais sensíveis e específicos para investigação da autenticidade de gêneros alimentícios de origem animal. A substituição total ou parcial de carne, leite ou derivados, de outra espécie animal que não a declarada no rótulo dos produtos, compromete a natureza e a qualidade destes produtos, prejudicando os direitos de escolha dos consumidores, que podem estar relacionados a recomendações médicas e nutricionais, ao valor econômico do produto ou sobre os hábitos e/ou restrições alimentares específicos de cada cultura. A identificação das espécies animais que deram origem aos produtos cárneos e lácteos e importante para a rastreabilidade dos alimentos. Embora matrizes alimentares tenham composição complexa e variável, técnicas biomoleculares têm sido cada vez mais utilizadas para a identificação de espécies animais, uma vez que tem sido demonstrada a confiabilidade, especificidade, rapidez e alta sensibilidade, mesmo quando utilizadas em amostras mistas. Esta revisão teve como objetivo apresentar os principais métodos moleculares que podem ser utilizados para a detecção da adulteração de espécies em derivados cárneos e lácteos, incluindo métodos já bem estabelecidos, tais como a reação em cadeia da polimerase (PCR), bem como as tecnologias mais avançadas, como a PCR em tempo real, os métodos de sequenciamento de DNA de ultima geração e o biochip de DNA ou DNA microarray. Esses métodos moleculares vêm sendo utilizados, com sucesso, na detecção e quantificação de DNA exógeno em amostras de alimentos, mesmo que este DNA esteja presente em pequenas quantidades.The increase in the population’s acquisition power in emerging countries like Brazil has resulted in increased consumption of meat, milk and their derivatives, and a consequent growing surveillance regarding the responsibility of maintaining the quality of these food products. The total or partial replacement by other than the species declared on the product label in meat, milk or derived products compromises the nature and quality of these products, hurting consumer choice rights, which may be based on medical and nutritional recommendations, the economic value of the product or habits and/or dietary restrictions of each specific culture. Species identification in dairy and meat products is important in food traceability. Although food matrices are complex and variable, biomolecular techniques are gradually being applied for species identification, having proven increasingly reliable, fast, specific and highly sensitive, even in mixed samples. For these reasons, this review intends to show the main molecular methods applied to adulteration detection in dairy and meat derivatives, including an already established method, such as the polymerase chain reaction (PCR), as well as more advanced technologies, such as real-time PCR, next-generation DNA sequencing methods and DNA biochip or DNA microarray, which have been gradually applied to the detection and quantification of exogenous DNA in food samples, even if present in small amounts

Comparing protocols for preparation of DNA-free total yeast RNA suitable for RT-PCR

BACKGROUND: Preparation of RNA free from DNA is a critical step before performing RT-PCR assay. Total RNA isolated from several sources, including those obtained from Saccharomyces cerevisiae, using routine methodologies are frequently contaminated with DNA, which can give rise to amplification products that mimic the amplicons expected from the RNA target. RESULTS: We investigated the efficiency of two DNase I based protocols for eliminating DNA contaminations from RNA samples obtained from yeast cells. Both procedures are very efficient in eliminating DNA contamination from RNA samples and entail three main steps, which involve treating of RNA samples with DNase I, inhibition of the enzyme by EDTA and its subsequent inactivation at 65°C. The DNase I treated samples were further purified with phenol: chloroform followed by precipitation with ice-cold ethanol (protocol I) or, alternatively, they were directly used in RT-PCR reactions (protocol II). Transcripts from ACT1, PDA1, CNA1, CNA2, TPS1 and TPS2 analyzed after each treatment showed that all mRNAs tested can be amplified if total RNA was extracted and purified after DNase I treatment, however, only TPS1, TPS2 and ACT1 mRNAs were amplified without extraction/purification step. CONCLUSION: Although more laborious and requiring a higher initial amount of material, the inclusion of an extraction and purification step allows to prepare RNA samples that are free from DNA and from low molecular contaminants and can be applied to amplify any Saccharomyces cerevisiae mRNA by RT-PCR

Dietary supplementation of a fiber-prebiotic-gut health promoter blend in extruded diets fed to dogs

The pet population is growing at a fast pace and 91.7% of 2,668 American pet owners consider their dog as part of their family. Thus, the importance of longevity and health of companion animals has been a constant concern for pet parents, and diet plays an important role in that. The use of prebiotics and dietary fibers have gained renewed interest in the pet food industry as a strategy to modulate gut health. Dietary fibers are heterogeneous compounds that exert different physiological responses and health benefits depending on their physical and chemical characteristics. Different types of prebiotics can be incorporated in diets of dogs and their efficacy is related to their structure, form of supplementation, and dosage. Both prebiotics and dietary fibers are non-digestible ingredients that may confer benefits to the host by selectively stimulating beneficial intestinal bacteria and affecting rate of fermentation and concentrations of fermentative end-products. Therefore, the aim of this experiment was to evaluate the effects of a prebiotic and dietary fiber blend with or without a gut health promoter on outcomes pertaining to gastrointestinal health and nutrient digestibility by adult dogs. Four diets containing either 5% of cellulose (CT), 5% fiber and prebiotic blend (FP), 0.02% of a gut health promoter additive (GP), or 5% fiber and prebiotic blend plus 0.02% of gut health promoter (FG) were formulated to meet or exceed the AAFCO (2017) nutritional requirements of adult dogs. Eight adult female beagles (mean age 4.2 ± 1.1 yr; mean BW = 10.8 ± 1.4 kg; mean BCS = 5.8 ± 0.6) were randomly assigned to one of the four dietary treatments using a replicated 4 x 4 Latin square design. Each experimental period consisted of 14 days (10 days of diet adaptation + 4 days of total and fresh fecal and total urine collection). Food was offered twice daily and fed to maintain body weight. Food intake and total fecal and urine output were measured and sampled for macronutrient analyses and digestibility calculations. Blood samples were collected at the end of each period for serum chemistry analysis and complete blood count. A fresh fecal sample from each dog was collected within 15 minutes of defecation and analyzed for dry matter (DM), phenols and indoles, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), and microbiota. The data were analyzed using The MIXED procedure using SAS, version 9.4. Total DNA from fresh fecal samples was extracted using Mo-Bio PowerSoil kits, sequencing was performed on a MiSeq and data were analyzed using QIIME 1.9.1. All animals remained healthy throughout the study, with serum metabolites being within reference ranges for adult dogs. All diets were well accepted by the dogs, resulting in similar (P > 0.05) daily food intakes among treatments. Likewise, fecal output and scores did not differ (P > 0.05) among dietary treatments, with the latter being within an ideal range (2.5-2.9). All diets were highly digested by dogs, and had a similar (P > 0.05) apparent total tract digestibility (ATTD) of dry matter (DM) (81.6-84.4%), organic matter (OM) (86.4-87.3%), and crude protein (CP) (86.6-87.3%). However, ATTD of total dietary fiber (TDF) was greater for dogs fed the FG diet (P 0.05). Fecal concentrations of isobutyrate and isovalerate were greater for dogs fed CT (P < 0.05) compared to dogs fed the other three treatments. No shifts in fecal microbial richness and diversity were observed when dogs consumed diets containing the fiber and prebiotic blend and (or) the gut health promoter additive. Overall, the data suggest that dietary supplementation of fiber and prebiotic blend were well tolerated by dogs, did not cause detrimental effects on fecal quality or nutrient digestibility, and resulted in beneficial shifts in fecal fermentative end-products that may support gut health. They also suggest a potential synergistic effect between fiber and prebiotic blend wth gut heath promoter that warrants further investigation