Dissertação(mestrado)- Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola de Química e Alimentos, 2008. / Submitted by Caroline Silva (krol_bilhar@hotmail.com) on 2012-09-17T00:53:33Z No. of bitstreams: 1 plm dissertao final.pdf: 556339 bytes, checksum: b19e5b6f838d349df2567703824482ef (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-09-18T21:50:15Z (GMT) No. of bitstreams: 1 plm dissertao final.pdf: 556339 bytes, checksum: b19e5b6f838d349df2567703824482ef (MD5) / Made available in DSpace on 2012-09-18T21:50:15Z (GMT). No. of bitstreams: 1 plm dissertao final.pdf: 556339 bytes, checksum: b19e5b6f838d349df2567703824482ef (MD5) Previous issue date: 2008 / A anemia ferropriva é a forma mais grave de carência de ferro, sendo a deficiência nutricional mais comum encontrada no mundo. As misturas à base de farelos de cereais ou multimisturas (MM) têm sido uma alternativa para fornecer nutrientes a populações infantis de baixa renda, visando a promoção de um crescimento adequado, a prevenção e tratamento da anemia, diminuição de diarréia, etc. O objetivo deste estudo é avaliar a eficácia de diferentes composições de multimistura na biodisponibilidade de nutrientes como ferro e proteína através de ensaio biológico. Foram formuladas 2 MM com adição da microalga Spirulina platensis diferindo quanto ao tipo de farelo (trigo ou arroz); uma MM conforme preconizado pela Pastoral da Criança; uma dieta controle à base de caseína; outra semelhante à controle porém deficiente em ferro e uma aprotéica. Inicialmente os 48 animais foram divididos em 2 grupos de 24 ratas cada, um para depleção de ferro e outro para depleção de proteína. Após este período, foram divididas em grupos de 6 animais segundo o tipo de dieta ofertada: controle (caseína); MM com farelo de arroz e Spirulina (MAS); MM com farelo de trigo e Spirulina (MTS) e MM Pastoral da Criança (MPC). As rações foram administradas durante 21 dias e, ao final deste período, os animais foram sacrificados para análise de índices bioquímicos, hemograma e relação dos órgãos com peso corporal. As rações foram avaliadas nutricionalmente através do coeficiente de eficiência alimentar (FER), razão de eficiência líquida protéica (PER), coeficiente de utilização líquida de proteína (NPR) e digestibilidade verdadeira in vivo (DV). Foi realizada análise de variância em todos os resultados, sendo as médias comparadas entre si pelo teste de Tukey (p<0,05). Os resultados desse estudo demonstraram que as ratas que se alimentaram das MM com farelo de arroz apresentaram maior ganho de peso do que as que ingeriram MM com farelo de trigo. As dietas com Spirulina também causaram maior ganho de peso que a MM sem a microalga. Todos os índices bioquímicos testados encontraram-se dentro da normalidade para a espécie e não diferiram entre os grupos. Como era esperado, a DC apresentou maiores valores de FER, PER, NPR e DV que as MM, e dentre essas, as dietas MAS e MTS tiveram valores mais elevados desses indicativos biológicos que a MPC, indicando que a adição da Spirulina aumentou a qualidade nutricional dessas MM. / Iron deficiency anemia is the most serious iron deficiency and the commonest nutritional need worldwide. Cereal-oat-based mixtures or multimixes (MM) have been considered as alternatives to supply nutrients to low-income infant populations, to promote adequate growth, prevent and treat anemia, fight diarrhea, etc. The aim of this study is to evaluate by a biological assay the efficacy of different multimixes formulations with respect to the nutrients bioavailability such as iron and protein. Two MM were produced including the microalgae Spirulina platensis distinct only from the bran used (wheat or rice); one MM as suggested by the Child Pastoral; a control casein-based diet; another similar to control but lacking iron and a protein free diet. First the 48 animals were split into two groups of 24 female rats each, one group followed iron depletion and the other protein depletion. Then, six-animal groups were created according to the diet they were fed: control (casein); rice bran plus Spirulina MM (MAS); wheat bran plus Spirulina MM (MTS) and Child Pastoral MM (MPC). Animals were fed during 21 days and, later they underwent euthanasia to run biochemical analyses, hemogram and to assess the organ/bodyweight ratio. Diets were evaluated nutritionally by the food efficiency ratio (FER), protein efficiency ratio (PER), net protein ratio (NPR) and in vivo digestibility (DV). Analysis of variance was carried out for all results and mean values were compared by Tukey's test (p<0.005). The results showed that rats fed with rice-bran MM presented higher weight gains than those fed with wheat-bran MM. Diets containing Spirulina also resulted in higher weight gains compared to Spirulina free diets. All biochemical parameters tested were within normal range for the species and were no different between groups. As expected, DC presented higher FER, PER, NPR and DV than MM diets, and within MM diets, MAS and MTA resulted in higher levels of these biological parameters than MPC, pointing out to a conclusion that the addition of Spirulina improved the MM nutritionally.

Quantifier la totalité des apports atmosphériques, notamment particulaires, est nécessaire pour mieux comprendre les cycles biogéochimiques en vue d'une gestion durable des écosystèmes forestiers. En effet, l'intensification des récoltes de bois-énergie induit une pression nutritive supplémentaire sur les forêts. Le but de ce travail est de combler les lacunes concernant le dépôt atmosphérique particulaire (taux de dépôt, composition minéralogique et chimique), ainsi que d'étudier son influence sur les cycles biogéochimiques forestiers. Pour ce faire, un échantillonnage de 2 ans a été mis en place dans 4 hêtraies de la moitié Nord de la France. Un développement métrologique a été nécessaire pour concevoir les capteurs hors et sous canopée et pour séparer les particules de la phase dissoute puis compartimenter le dépôt particulaire en fonction du modèle conceptuel organo-minéral établi dans cette étude. Les résultats obtenus valident ce modèle et montrent (i) un taux de dépôt annuel de 19±3 kg.ha-1.an-1 de minéraux peu solubles témoignant d'origines diverses, (ii) des flux de nutriments inférieurs à ceux des dépôts dissous et de l'altération des minéraux du sol mais qui contribuent à améliorer la fertilité des forêts, (iii) un captage supplémentaire induit par la canopée et (iv) une dissolution des particules minérales lors de leur transport atmosphérique qui enrichit les précipitations en nutriments. Un échantillonnage optimisé sur le long terme est indispensable pour confirmer et préciser les tendances observées, en particulier concernant les épisodes de très fort dépôt particulaire et le dépôt sous la canopée / Quantifying the little-known inputs of atmospheric particulate deposition (APD) is critically important for a sustainable management of forest ecosystems. Indeed, harvesting and subsequent nutrient losses are going to increase so as to meet the demand in renewable energy, including fuel-wood. This work aims at filling this gap by (i) describing the deposition rate, mineralogical and chemical compositions of APD and (ii) evaluating the influence of APD nutrient inputs on forest biogeochemical cycles. To do so, 4 beech stands in North French forests were equipped for a 4-week sampling. After a metrological development, samplers out of and below canopy were used for a 2-year sampling, as well as methods to separate APD from atmospheric dissolved deposition. These methods were conceived to separate the organic and mineral fractions of APD according to the conceptual model designed in this work. My results validated this model and indicated (i) a quite constant deposition rate of 19±3 kg.ha-1.year-1 of hardly soluble minerals over the North of France, made of various minerals suggesting heterogeneous sources of particles, (ii) nutrient inputs inferior to those of atmospheric dissolved deposition and soil weathering, but improving ecosystem fertility, (iii) an interception effect of the canopy, and (iv) the dissolution of mineral particles in the atmosphere which enriched atmospheric dissolved deposition in nutrients. Extending and optimizing the sampling would allow confirming and clarifying these results, especially concerning high atmospheric load periods and APD below canopy

Dans les écosystèmes forestiers pauvres en nutriments, les minéraux du sol constituent la principale source de nutriments inorganiques nécessaires à leur bon fonctionnement. Néanmoins ces nutriments ne sont pas directement accessibles aux racines des arbres. C'est l'action conjointe de facteurs abiotiques, comme le pH ou la circulation de l'eau, et biotiques comme les racines ou les microorganismes du sol dont les bactéries, qui vont conduire à l'altération de ces minéraux. A ce jour, nos connaissances sur les communautés bactériennes impliquées dans le processus d'altération et leur distribution dans des sols forestiers restent limitées, notamment à des habitats tels que la rhizosphère et la mycorhizosphère. Les objectifs de cette thèse étaient de caractériser les communautés bactériennes colonisant les minéraux du sol et leur aptitude à altérer les minéraux et enfin d'identifier les gènes bactériens impliqués. La combinaison d'approches cultivable, non cultivable et de biogéochimie sur des minéraux enterrés pendant 4 ans dans un sol forestier, a démontré que leur surface était colonisée par des communautés bactériennes spécifiques, capables d'altérer les minéraux et présentant des capacités métaboliques limitées, suggérant que ce support pourrait être considéré comme un habitat : la minéralosphère. La relation minéral/bactéries a été testée in situ via un amendement minéral sur une plantation et a mis en évidence l'impact de la disponibilité en nutriments sur la structuration des communautés bactériennes capables d'altérer les minéraux. L'étude génétique réalisée sur la souche modèle PML1(12) a révélé l'implication de plusieurs mécanismes dans la fonction altération / In nutrient-poor forest ecosystems, minerals are the main source of inorganic nutrients for the long lasting functioning of the forests. However, these nutrients are not directly accessible to the tree roots. It is the joined action of abiotic factors, such as pH and water circulation, and biotic factors such as tree roots and soil microorganisms, and notably bacteria, which leads to the solubilisation of these minerals. To date, our knowledge of the bacterial communities involved in the mineral weathering process and their distribution in forest soils is very limited and remains restricted to habitats such as the rhizosphere and mycorrhizosphere. The goals of this PhD thesis were to characterise the mineral associated bacterial communities, their ability to weather minerals and finally to identify the bacterial genes involved in the mineral weathering process. The combination of geochemical, cultivation-dependent and -independent approaches applied on minerals grounded in a forest soil during 4 years, revealed that the mineral associated bacterial communities were specific, able to weather minerals and had restricted metabolic abilities. These results suggest that minerals could be considered as a true ecological habitat: the mineralosphere. The mineral/bacteria relationship was tested in situ through a mineral amendment applied on a small-scale plantation, which has highlighted that the nutrient availability impacted the functional structure of the mineral weathering bacterial communities. At least, random mutagenesis applied on a model mineral weathering bacterial strain revealed that its mineral weathering ability resulted from several molecular mechanisms