Made available in DSpace on 2017-07-10T17:47:58Z (GMT). No. of bitstreams: 1 Camila_Ducati.pdf: 1229241 bytes, checksum: 0880bcc64cf9d89389cf4eef6e2a7e0b (MD5) Previous issue date: 2014-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Were conducted for two years, with two studies to evaluate the use of oat long cycle Iapar 61 single or grown in association with legumes birdsfoot trefoil, with planting of corn in succession as a summer crop. The first study evaluated the structural, production characteristics, nutritional value of oat (Avena strigosa Iapar 61) grown single or associated with birdsfoot trefoil (Lotus corniculatus cv. St. Gabriel). The second experiment was conducted in two years with the aim to evaluate the structural , production characteristics , gas exchange IRGA (Infra Red Gas Analyser , Li - 6400XT , Licor , Lincoln , Nebraska) and chlorophyll content (SPAD index) of maize grown in succession to winter crops mentioned above . In the first experiment, two courts of oats in the first year and grazing periods in the second year, with average intervals of 30 days. The experimental design was a randomized complete block design with split plot, with the first year: two cropping systems: single or intercropped with birdsfoot trefoil with two periods of four replicates and oats oatmeal. In the second year, four tillage systems: conventional tillage oats, oat stubble tillage on corn, oats overseeded area of birdsfoot trefoil and single, with three cycles of growth and four replications. In the second study with corn, the experimental design used in the first and second year was a randomized split plot with blocks respectively. The following winter crops Corn was studied in succession: oat conventional tillage, no-till oats, oats in combination with birdsfoot trefoil, birdsfoot single, oats associated with nitrogen fertilization on ryegrass and oats associated with ryegrass nitrogen fertilization, with four replications. After planting corn the second year, we assessed the structural features for 70 days. Before the corn harvest, were picked manually ears of corn in three rows of four meters, which evaluated the number of grain rows, number of kernels per row, ear diameter, ear length, subsequent to these reviews, was made the threshing of grain for measurement of productivity data. The findings of the first study show that oats have reduced their production when combined with birdsfoot dry matter, but the total production (oat + birdsfoot trefoil) equates to the other treatments. In the first year dry matter yield of oats was higher when associated with birdsfoot the second cut (3750 kg ha - 1) compared to that obtained in the tillage of oat (2599 kg ha -1). In the second year, the highest dry matter production of oat occurred before the second grazing under no-tillage (4451.98 kg ha - 1). Oats elevates the apical meristem with the succession of grazing or cutting. The oat presents before the first grazing, high nutritional value, with high average levels of protein (22.25 %) for all treatments. However, at the end of its cycle the association of birdsfoot trefoil with oats, helped to raise the crude protein content of forage as this is in the final stage of its cycle. In vitro digestibility of DM was high for both oat grown under conventional tillage (73.04 %) and direct (77.05 %), and for birdsfoot trefoil (78.37 %), but decreased at the end of the cycle oat. There was no benefit to the cultivation of corn grown after legume and should performed new tests assessing possible causes, including allelopathic effect and competition among plants / Foram conduzidos por dois anos, dois estudos com o objetivo de avaliar o uso da aveia preta de ciclo longo Iapar 61 cultivada solteira ou em associação com a leguminosa cornichão, com plantio do milho em sucessão como cultura de verão. No primeiro estudo avaliaram-se as características estruturais, produtivas, valor nutricional da aveia preta (Avena strigosa Iapar 61) cultivada solteira ou associada ao cornichão (Lotus corniculatus cv. São Gabriel). O segundo experimento foi conduzido em dois anos com o objetivo de avaliar as características estruturais, produtivas, trocas gasosas IRGA (Infra Red Gas Analyser, Li-6400XT, Licor, Lincoln, Nebrasca) e teor de clorofila (Índice SPAD), do milho cultivado em sucessão aos cultivos de inverno citados anteriormente. No primeiro experimento avaliou-se dois cortes da aveia preta no primeiro ano e períodos de pastejo no segundo ano, com intervalos médios de 30 dias. O delineamento experimental foi em blocos casualizados com parcelas subdivididas no tempo, sendo no primeiro ano: dois sistemas de cultivo: aveia solteira ou aveia consorciada com cornichão com dois períodos de avaliação e quatro repetições. No segundo ano, quatro sistemas de cultivo: aveia plantio convencional, aveia plantio direto sobre palhada do milho, aveia sobressemeada em área de cornichão e cornichão solteiro, com três ciclos de crescimento e quatro repetições. No segundo estudo com milho, o delineamento experimental adotado no primeiro e segundo ano foi em blocos casualizados com parcelas subdivididas no tempo respectivamente. O milho foi estudado em sucessão as seguintes culturas de inverno: aveia preta plantio convencional, aveia preta plantio direto, aveia em associação com cornichão, cornichão solteiro, aveia associada com azevém com adubação nitrogenada e aveia associada com azevém sem adubação nitrogenada, com quatro repetições. Após o plantio do milho do segundo ano, avaliou-se as características estruturais por 70 dias. Antes da colheita do milho, colheram-se manualmente as espigas de três fileiras de milho em quatro metros, onde avaliaram-se o número de fileira de grãos, número de grãos por fileira, diâmetro de espiga, comprimento de espiga, posterior a essas avaliações, foi realizada a trilhagem das espigas para mensuração dos dados de produtividade. Os resultados encontrados no primeiro estudo demonstram que a aveia tem sua produção de matéria seca reduzida quando em associação com o cornichão, mas a produção total (aveia+cornichão) iguala-se aos demais tratamentos. No primeiro ano a produção de matéria seca da aveia preta foi superior quando associada com cornichão no segundo corte (3750 kg ha-1) em comparação ao obtido no sistema de plantio direto da aveia preta (2599 kg ha-1). No segundo ano, a maior produção de matéria seca da aveia preta ocorreu antes do segundo pastejo sob sistema de plantio direto (4451,98 kg ha-1). A aveia eleva o meristema apical com a sucessão de pastejos ou cortes. A aveia preta apresenta antes dos primeiros pastejos, elevado valor nutricional, com altos teores médios de proteína (22,25%) em todos os tratamentos. Entretanto, no final do seu ciclo a associação do cornichão com a aveia, contribuiu para elevar os teores de proteína bruta da forragem visto que esta encontra-se em estágio final do seu ciclo. A digestibilidade in vitro da MS foi elevada tanto para aveia preta cultivada sob sistema de plantio convencional (73,04%) e direto (77,05%), quanto para o cornichão (78,37%), decrescendo com o final do ciclo da aveia. Não foi verificado benefícios para o cultivo do milho em sucessão a leguminosa, devendo realizados novos ensaios avaliando possíveis causas, entre elas efeito alelopático e competição entre plantas

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-26T10:38:54Z No. of bitstreams: 2 Tese - José Tiago das Neves Neto - 2015.pdf: 1371547 bytes, checksum: a079c3c4597fc85eeef5c725389bcc04 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-26T10:39:33Z (GMT) No. of bitstreams: 2 Tese - José Tiago das Neves Neto - 2015.pdf: 1371547 bytes, checksum: a079c3c4597fc85eeef5c725389bcc04 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-26T10:39:33Z (GMT). No. of bitstreams: 2 Tese - José Tiago das Neves Neto - 2015.pdf: 1371547 bytes, checksum: a079c3c4597fc85eeef5c725389bcc04 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-04-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The manipulation of ruminal fermentation is a valuable tool aiming at increasing productivity and efficiency by using resources for animal feed. There are different kinds of tools, such as homogeneous mixing of feed, appropriate trough management, correct feed formulation, and the use of compounds (additives) aimed at assisting rumen fermentation process. The use of antibiotics in foods for animals as growth promoters is facing a social barrier, because of the waste and bacterial resistance that these products can be generating. For that reason the use of antibiotics for this end or at the diet of ruminants has been banned from the EU since January 2006. Therefore, some technologies have been developed to replace these products, and the use of vegetable extracts in ruminants nutrition as ruminal fermentation modulators have been largely studied. Some plants are rich in active compounds with antimicrobial power that makes them useful for animal nutrition. The crude extract of Pterodon Emarginatus Vogel presents sesquiterpenes and diterpenes in its composition, and β-caryophyllene is the most representative compound. Due to the limitations of using unknown products in animal nutrition, the techniques of in vitro digestibility and metabolic studies with animals cannulated in the rumen are largely used at the first stages of research. The objective of this study was to evaluate different dosages of Pterodon Emarginatus Vogel crude extract in vitro ruminal fermentation through a system of continuous culture of double flow. The treatments corresponded to four doses: 0%; 0.6%, 0.12%; and 0.24% of Pterodon Emarginatus Vogel crude extract in dry matter (DM) of the provided diet and a treatment with Sodium Monensin (30 ppm). The experimental design was entirely in randomized blocks with four replications and five treatments. The in vitro test showed a difference of (P<0.05) in the DM and OM digestibility between the treatments 0.24% of Pterodon Emarginatus Vogel crude extract and monensin. There was no difference (P>0.05) in the digestibility of NDF and ADF. The addition of the Pterodon Emarginatus Vogel extract increased the digestibility of DM and OM when compared with Sodium Monensin without effects on NDF and ADF. The treatments affected (P<0.05) acetic acid concentration, and the concentration 0.24% showed a decrease when compared with control treatment. The same happened with the relation between acetic and propionic acids, where 0.24% treatment produced a lower ratio compared with control and 0.06% treatments. The extract of Pterodon emarginatus Vogel has potential to modulate the ruminal fermentation because of its effect on ruminal microorganisms, and it is dose-dependent. Thus it can be used as an additive to manipulate ruminal fermentation and probably as a substitute of the sodic monensin. However, more studies must be carried out to answer the questions about the use of this substances, to clarify the effects of this products on the ruminal microorganisms, its effects on animal metabolism, parameters of in vivo ruminal fermentation, quantify the dosages to be used and quantify animal performance gain. The Culture System in Continuous Flow revealed to be an important alternative method and it showed accuracy for ruminal digestibility studies. / A manipulação da fermentação ruminal é valiosa ferramenta na busca do aumento da produtividade e da eficiência na utilização dos recursos destinados à alimentação animal. Existem diversas ferramentas como a mistura uniforme da ração, o manejo adequado de cocho, a formulação correta da ração e a utilização de compostos que visam auxiliar o processo fermentativo do rúmen denominados aditivos. O uso de antibióticos como promotores de crescimento em alimentos para animais tem enfrentado resistência, devido aos resíduos e a resistência bacteriana que estes produtos podem gerar. Por isso, o uso de antibióticos em sistemas de produção de ruminantes foi proibido na União Europeia em janeiro de 2006. Desta forma, algumas tecnologias têm sido desenvolvidas para substituir estes produtos e dentre estes, os extratos vegetais vêm sendo amplamente estudados na nutrição de ruminantes como moduladores da fermentação microbiana ruminal. Estas plantas são ricas em compostos ativos com poder antimicrobiano tornando-as úteis na nutrição animal como aditivos. O óleo bruto de sucupira apresenta, em sua composição sesquiterpenos e diterpenos sendo, o β-cariofileno, o composto de maior concentração. Diante das limitações da aplicação de produtos desconhecidos na alimentação animal, as técnicas de digestibilidade in vitro e estudos metabólicos com animais canulados no rúmen são recomendados nas etapas iniciais da pesquisa. Com o presente trabalho objetivou-se avaliar diferentes doses do óleo bruto de Sucupira sobre a fermentação microbiana ruminal in vitro através de um sistema de cultura contínua de duplo fluxo. Os tratamentos foram constituídos de quatro doses: 0%; 0,06%; 0,12%; 0,24% na matéria seca (MS) da dieta fornecida do extrato bruto de Sucupira e um tratamento com Monensina Sódica (30 ppm). O delineamento experimental realizado foi em blocos inteiramente casualizados com quatro repetições e cinco tratamentos. No ensaio in vitro, houve diferença (P<0,05) na digestibilidade da MS e MO entre o tratamento 0,24% do extrato de sucupira e os tratamentos controle e monensina. Não se observou diferenças (P>0,05) na digestibilidade da FDN e FDA. A adição do extrato de Pterodon emarginatus Vogel (Sucupira) aumentou a digestibilidade da MS e MO comparados com a Monensina Sódica, sem efeitos na DFN e DFA. A concentração do ácido acético foi afetada (P<0,05) pelos tratamentos, observando uma diminuição da concentração para o tratamento 0,24% comparado com o tratamento controle. O mesmo ocorreu com a relação entre os ácidos acético e propriônico, onde o tratamento 0,24% ocasionou uma menor relação comparado com os tratamentos controle e 0,06%. O extrato de Pterodon emarginatus Vogel (Sucupira) tem potencial de modular a fermentação ruminal devido ao seu efeito nos microrganismos ruminais, sendo seu efeito dose dependente, podendo ser usado como aditivo para manipular a fermentação no rúmen e ser um provável substituto da monensina sódica, porém mais estudos devem ser realizados para elucidar e responder as dúvidas referentes a utilização destas substancias, como esclarecer os efeitos desses produtos sobre os microrganismos ruminais, seus efeitos no metabolismo animal, nos parâmetros de fermentação ruminal in vivo, quantificar as doses a serem utilizadas e quantificar os ganhos em desempenho animal. O Sistema de Cultura em Fluxo Contínuo mostrou ser uma importante metodologia alternativa e de precisão para o estudo de digestibilidade ruminal.

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Made available in DSpace on 2014-08-20T13:42:10Z (GMT). No. of bitstreams: 1 Tese_Renata_Schmidt_Filgueras.pdf: 2801681 bytes, checksum: 977f5228a16ea0addcff2a8a6f4e1cd3 (MD5) Previous issue date: 2010-07-20 / Biochemical characteristics and oxidative stability during chilling and frozen were studied in M. Gastrocnemius pars interna (GN) and M. Iliofiburalis (IF) of rhea americana. The histochemical and morphometrical study was also conducted to determine fibre types and structural and ultrastructural differences between GN and IF muscles of rhea. Finally, the in vitro protein digestibility and the nutritional value of proteins were also investigated after storage/ageing and cooking in GN muscle. The ultimate pH was similar in both muscles, but the glycolytic potential (GP) was significantly higher in IF than in GN muscle. Under chilling (4 °C) and air-packaging rhea muscles exhibited differences in their stability. In particular, the IF muscle presented high colour instability and high lipid and protein oxidations after 5 days of air-packaged storage. Under chilling (4 °C) and vacuum-packaging both muscles were highly stables during 28 days and did not present evidences of oxidation. Under frozen (-20 °C) GN muscle was perfectly stable during 180 days, but IF muscle presented evidences of lipid and myoglobin oxidation after 90 days of storage. The fatty acid composition, higher lipid content and the higher myoglobin concentration in IF than in GN muscle could partially explain the instability of IF muscle during air-packaging, but the high residual glycogen observed in biochemical analysis also seemed to be involved in the occurrence of the oxidative process. The histochemical analysis of rhea limb muscles demonstrated the presence of only one type of fibres in both GN and IF muscles, i.e. fast-twitch oxidative and glycolytic (FOG) fibres. The homogeneity of fibres was evident after m-ATPase, SDH and glycogen staining reactions. In addition, the ultrastructural observation of rhea myofibrils showed contracted and stretched areas, as well as abundant glycogen and numerous mitochondria, mainly in IF muscle. Finally, the study of protein nutritional value and protein rate of digestion indicated that storage/ageing had less impact than cooking on protein oxidation and aggregation. After cooking (100 °C, 30 min) the aggregates increased 400% and the content of aromatic amino acids decreased. The nutritional value of proteins was affected by cooking, as demonstrated by the decrease of pepsin activity rate. However, trypsin chymotrypsin activities were stable after heat treatment. / As características bioquímicas e a estabilidade oxidativa durante o armazenamento foram estudadas nos músculos Gastrocnemius pars interna (GN) e Iliofiburalis (IF) de emas (rhea americana). Além disso, o estudo histoquímico e morfológico foi conduzido para determinar o tipo metabólico e contráctil das fibras musculares e as diferenças estruturais e ultra-estruturais entre os dois músculos. Por fim, a taxa de digestão e o valor nutricional das proteínas miofibrilares foram investigados após armazenamento/maturação e cocção da carne do músculo GN. O pH final de ambos os músculos foi semelhante, mas o potencial glicolítico (PG) do músculo IF foi significativamente superior ao do músculo GN. Sob refrigeração (4 °C) e embalagem permeável ao oxigênio os músculos de ema apresentaram diferenças de estabilidade oxidativa. Particularmente, o músculo IF mostrou grande instabilidade de cor e altos níveis de oxidação lipídica e protéica ao final de cinco dias de armazenamento. Sob refrigeração e embalagem a vácuo ambos os músculos foram estáveis durante 28 dias, não apresentando evidências de oxidação. Sob congelamento, enquanto o músculo GN foi estável durante 180 dias, o músculo IF mostrou indícios de oxidação de lipídios e da mioglobina a partir de 90 dias. O perfil dos ácidos graxos, a maior quantidade de lipídios totais e a maior concentração de mioglobina do músculo IF explicam parcialmente sua maior instabilidade oxidativa quando exposto ao oxigênio. Porém, a grande quantidade de glicogênio residual observada no músculo IF após análise bioquímica também parece estar envolvida na ocorrência dos processos oxidativos. A análise histoquímica dos músculos GN e IF de emas mostrou a presença de somente um tipo de fibra muscular em ambos os músculos, isto é, todas as fibras analisadas foram classificadas como fibras de metabolismo misto (oxidativo e glicolítico) e contração rápida. A homogeneidade do tipo de fibras foi evidenciada após a aplicação de técnicas histoquímicas que determinaram a atividade da m-ATPase, a atividade da succinato desidrogenase (SDH) e presença de glicogênio muscular. Além disso, a observação ultra-estrutural das miofibrilas mostrou áreas de contração e áreas de extensão, assim como abundância de mitocôndrias e de glicogênio, principalmente no músculo IF. Por fim, o estudo do valor nutricional e da taxa de digestão das proteínas miofibrilares da carne de ema indicaram que a maturação foi menos impactante do que a cocção sobre a oxidação das proteínas e formação de agregados. Após cocção (100 °C, 30 min), a quantidade de agregados aumentou até 400% na carne de ema e os teores de amino ácidos aromáticos caíram. A taxa de digestão pela pepsina diminuiu após tratamento térmico, enquanto a taxa de digestão pela tripsina/quimotripsina manteve-se estável.

Cette étude a été menée dans le but d’explorer les nouvelles sources de protéines à valeur nutraceutique. Les graines de Ricinodendron heudelotii (Bail. Pierre ex Pax) et de Tetracarpidium conophorum (Müll. Arg) ont d’abord été cuites dans de l’eau bouillante pendant 90 et 30 min qui sont respectivement leurs temps optimums de cuisson. Après délipidation et tamisage des tourteaux, la fraction 400 - 500 µm s’est révélée la plus représentative avec plus de 70 % et riche en azote protéique (6–7% MS). Les concentrats et les isolats protéiques ont été préparés à partir des tourteaux respectivement dans l’eau distillée à pH 4,5 et dans une solution de NaOH à 0,2 % (R. heudelotii), une solution de NaCl 0,6 M (T. conophorum) à pH 11. Ces concentrats (65 – 75 % MS de protéines) et ces isolats protéiques (81 – 92 % MS de protéines) ont une composition physico-chimique différente (P < 0,05) de celle des tourteaux. Pour les deux Euphorbiacées, les capacités de rétention d’eau (367 – 467 g / 100 g d’échantillon), de rétention d’huile (256 – 410 g / 100 g d’échantillon) et moussante (68 – 71 %) sont maximales dans les isolats protéiques tandis que les capacités gélifiante (6 – 14 %) et émulsifiante (63 – 87 %) le sont dans les concentrats protéiques. Les teneurs en acides aminés essentiels des tourteaux de R. heudelotii et de T. conophorum sont comparables à celle de la protéine de référence. L’étude de la digestibilité enzymatique in vitro a montré que l’azote libéré après 6 h est supérieur à 90 % dans les concentrats et les isolats protéiques. La digestibilité protéique in vivo indique que le gain de poids des rats mâles âgés de 21 ± 3 jours durant 15 jours d’expérimentation ainsi que les paramètres de rétention azotée sont plus importants avec les régimes à base de l’aliment de référence (caséine) et du tourteau de T. conophorum. Les valeurs corrigées des paramètres de digestibilité par l’indice chimique des acides aminés laissent apparaître que le tourteau de T. conophorum renferme les protéines de très bonne qualité nutritionnelle, autant que la caséine / This study was conducted in order to look for alternative sources of proteins having nutraceutic value. The grains of Ricinodendron heudelotii (Bail.) and Tetracarpidium conophorum (Müll. Arg) were first cooked in boiled water at their optimal cooking time for 90 and 30 min respectively. After defating, sieving of the defatted cakes showed that samples with a granulometry of 400 - 500 µm were most representative (more than 70%), containing more proteic nitrogen (6–7 %). Protein concentrates and protein isolates were prepared from defatted cakes respectively in distilled water at pH 4.5 and in NaOH 0.2% (R. heudelotii) and NaCl 0.6M (T. conophorum) at pH 11. Physico-chemical properties of protein concentrates (65 – 75 % of proteins) and protein isolates (81–92 % of proteins) were different from those of the defatted cakes. Water holding (367 – 467 g / 100 g of sample), oil holding (256 – 410 g / 100 g of sample) and foaming capacities (68 – 71 %) were highest with protein isolates whereas gelling (6 – 14 %) and emulsion capacities (63 – 87 %) were highest with concentrates. The amounts of essential amino acids in both defatted flours were comparable to the value in FAO / WHO (2007) scoring pattern. Nitrogen liberated after 6 h of enzymatic digestibility was more than 90 % both in the proteins concentrates and isolates. In vivo studies carried out on 21 ± 3 days old Sprague Dawley male rats for 15 days showed that gain of weight and nitrogen retention parameters were higher for rats that consumed casein and T. conophorum defatted cake. Corrected values of nitrogen digestibility of the analysed samples showed that T. conophorum defatted cake contains protein source with good nutritional quality

Le taro (Colocasia esculenta L SCHOTT) est un tubercule d’une grande importance alimentaire au Tchad pour la consommation humaine et animale. La littérature sur les pratiques culturales et les technologies traditionnelles post-récolte des variétés tchadiennes demeure presque inexistante. Une enquête a donc été menée dans la région du Mayo-Kebbi (Tchad) où le taro est très cultivé. Il résulte qu’il existe principalement deux variétés de taro au Tchad : la variété « Gouning souol» ou variété locale qui est caractérisée par une âcreté importante et un temps de cuisson prolongé (6 à 8 h). Ces propriétés ont entraîné l’abandon de la culture de cette variété au profit de la variété « Gouning sosso » qui présente une âcreté moindre et un temps de cuisson plus court (45 à 60 minutes). Une technique traditionnelle pour réduire l’âcreté et diminuer le temps de cuisson consiste à tremper les tranches de taro frais soit dans l’eau, soit dans une solution de trempage de maïs ou soit dans une infusion de tamarin pendant 24 à 48 h selon l'intensité de l'âcreté. Après séchage au soleil, les cossettes sèches sont transformées en farine. Ces produits de transformation servent à la préparation de boules de pâtes, de bouillie, de soupes ou de beignets. Des analyses ont été effectuées sur une gamme d’échantillon de farine de taro produite conformément à la recette artisanale dans l’optique de comprendre l’effet de cette technologie traditionnelle. Des cossettes fraîches de taro ont été trempées pendant 0, 1 h, 3 h, 6 h, 12 h et 24 h dans de l’eau, ou dans une solution de trempage de maïs ou dans une infusion de tamarin. Chaque échantillon a ensuite été séché au soleil pendant 48 h puis broyé en farine. La matière sèche, les protéines brutes, les cendres, les fibres brutes, les macroéléments minéraux et oligoéléments ont été évalués dans le but de déterminer les effets du trempage traditionnel sur le profil nutritionnel du taro. La digestibilité in vitro de l’amidon sous l’action de l’α-amylase et la teneur en oxalates de différentes farines de taro ont été également déterminées. Il ressort de ces analyses que seul le trempage dans une infusion de tamarin a induit une baisse significative (P < 0,001) de la teneur en protéines brutes (de 3,26 % pour T0 à 2,68 % pour le traitement au tamarin à T24). L’infusion de tamarin n’a pas modifié la teneur en fibres brutes alors que les autres traitements l’ont assez significativement diminuée (P < 0,001). Toutes les méthodes de trempage ont entraîné une diminution significative des teneurs en minéraux, à l’exception d’une augmentation des teneurs en sodium (due à la qualité de l’eau des préparations) et en phosphore (probablement due à l’hydrolyse des phytates du maïs). Une perte significative en fer a été constatée passant de 144 mg/kg de MS (témoin) à 78 mg/kg de MS (échantillon traité à l’eau pendant 12 h), soit une perte de 45,83 %. La plus faible diminution de taux de fer est observée dans le cas de l'échantillon trempé dans l'infusion de tamarin avec une perte maximale de 31,25 % après 24 h. La teneur en zinc ne varie pas. Les procédés de trempage entraînent globalement une amélioration de la digestibilité du taro après une simple cuisson (95°C pendant 30 minutes) qui passe de 39,30 % (échantillon témoin non trempé) à 78,67 % pour le taro trempé dans l’eau. Après 3 h de trempage, la farine de taro traitée par la solution de maïs est significativement plus digestible (77,12 %) que les échantillons résultant de deux autres traitements [tamarin (60,86 %), eau (60,45 %)] qui sont statistiquement similaires. (...) / Colocasia esculenta L SCHOTT is a valuable tuber widely consumed in Chad by humans and livestock. There is very little available literature about the cultivation and the post-harvest traditional technologies of the Chadian varieties of taro. A survey was carried out in the Mayo-Kebbi region ( Chad) where taro is a widely cultivated. There are two main varieties of taro in Chad : the " Gouning souol " variety, a local variety characterized by an important level of acridity and the prolonged cooking time (6 to 8 hours). The presence of these properties led to the replacement of the cultivation of this variety by the " Gouning sosso " variety which presents a lower level of acridity and a shorter cooking time (45 to 60 minutes). A traditional process to reduce the acridity and decrease the cooking time consists in dipping the slices of fresh taro in the water, or in a corn solution or in a tamarind infusion for a period of 24 to 48 hours according to the intensity of the acridity. After drying in the sun, the dried chips are ground into flour. This flour is then used to prepare mixtures of porridge, soups and cakes. Analyses were carried out on samples of taro flour produced in accordance with the traditional methods of soaking to determine the effects of this traditional process. Fresh taro chips were dipped over a period of 0, 1, 3, 6, 12 and 24 hours in the water, or in the corn infusion or in the tamarind infusion. Each sample was then dried in the sun for 48 hours and ground into flour. Dry matter, crude protein, ash, crude fiber, minerals and various trace elements were assessed. The in vitro digestibility of taro starch using α-amylase enzyme and the amount of total oxalates in the different taro flour were also determined. The soaking in the tamarind infusion induced a significant (P < 0.001) decrease in protein content (from 3.26 % for the control sample to 2.68 % for the treatment with the tamarind infusion at T24). The other treatments (corn solution and water) reduced also the protein level of taro but not significantly. The crude fibre content was not affected by the tamarind infusion but decreased significantly in the other treatments at the threshold level of 5 %. All methods of soaking led to a significant decrease of the mineral contents, except for an increase in sodium (due to the quality of the water used to prepare solutions) and in phosphorus (probably due to the hydrolysis of phytates by the corn infusion). A significant loss in trace element (Iron) was observed, decreasing from 144 mg / kg of DM (control sample) to 78 mg / kg of DM (after 12 hours of water soaking) corresponding to a loss of 45.83 %. The lowest decrease in iron level was observed after the treatment by the tamarind infusion (31.25 % after 24 hours). All the soaking processes were seen to have improved the digestibility of taro flour. By simply cooking (at a temperature of 95°C for 30 minutes), the in vitro digestibility increased from 39.30 % for the control sample to 78.67 % for the water treated samples of taro. After three hours of soaking, the taro flour treated by the solution of corn becomes significantly more digestible (77.12 %) than by the two other treatments [tamarind (60.86 %), water (60.45 %)] that are statistically similar. (...)

MSCAGR (Animal Science) / Department of Animal Science / The objective of the study was to determine the effects of fertilisation with bio-digester slurry and the inclusion of carbohydrate additives at ensiling on the fermentation characteristics, chemical composition, ruminal degradability, and in vitro digestibility of Napier grass silage. Napier grass planted at the School of Agriculture Experimental Farm, University of Venda in 5 m x 4 m plots replicated three times in a completely randomised design and was irrigated with either biodigester slurry or no bio-digester slurry (tap water) for a period of 12 weeks. After 12 weeks, the Napier was freshly cut and ensiled for 90 days in 1 litre glass jars in a 2 (Control - tap water and slurry irrigation) x 4 (No additive, molasses, maize meal and brown sugar) factorial arrangement. Fermentation quality and nutritive composition were determined using standard protocols. The dry matter (DM) and crude protein (CP) ruminal degradability was determined in sacco by incubating feed samples in nylon bags (external dimension: 6 × 12 cm, pore size of 46 μm) in the rumen in three Bonsmara steers fitted with rumen cannulae for 0, 6, 12, 24, 48, 72, 96 and 120 hours (h). Parameters to describe the dynamics of ruminal degradability of DM and CP were obtained by fitting the data on the exponential equation P = a + b (1 - e-ct) using the NEWAY computer program, where “a” is the rapidly degradable fraction, “b” is the slowly degradable fraction and “c” is the outflow rate. The in vitro DM and CP degradability of rumen undegradable residue collected after 12, 24 and 48 h incubation was determined by sequential digestion in pepsin (abomasal) and pancreatin (small intestine) solutions. Fertilisation with bio-digester slurry increased (P <0.05) CP content of fresh cut Napier grass pre-ensilage. Bio-digester slurry fertilisation with molasses inclusion improved (P <0.05) the silage DM content which improved (P >0.05) fermentation characteristics with pH of 4.2 and lowest NH3-N of 13.3 g/kg. Other chemical compositions and fermentation characteristics were not affected (P >0.05) due to fertilisation x additives treatment combinations. No bio-digester slurry fertilisation with maize meal inclusion increased (P <0.01) DM degradability at 0 h incubation. As time progressed to 24 h, no biodigester slurry fertilisation with no additive included reduced (P <0.01) DM degradability with no difference (P >0.05) on other treatments. Potential DM degradability (a + b) of no bio-digester slurry fertilisation with no additive inclusion silage was reduced (P <0.01). The reduction was associated with low levels (P <0.01) of slowly degradable fraction “b”. In vitro DM and CP digestibility were not affected (P >0.05) due to fertilisation x additives treatment combinations. In conclusion, bio-digester slurry application improved the quality of fresh cut Napier grass, with the combination of bio-digester slurry fertilisation and molasses addition yielding the best silage quality.

MSCAGR (Animal Science) / Department of Animal Science / Forage and browse legumes play an important role in sustaining livestock in small holder farming systems in the tropics, mainly as a result of their contribution to economic and environmental sustainability of livestock production. The study was conducted to determine the chemical composition, ruminal degradability and in vitro digestibility of dry matter (DM) and crude protein (CP) of Dichrostachys cinerea and Bauhinia thonningii leaves. The browse tree leaves were harvested in the wild in Shayandima, Limpopo province. The leaves were collected, oven-dried, milled to pass through a 1.0 mm sieve and analysed for chemical composition in the Animal Science Nutrition Laboratory, at the University of Venda. The browse tree leaves were analysed for DM nitrogen, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Approximately 5 g of leaf sample milled to pass through through a 1 mm sieve were placed in nylon bags (external dimension: 6 × 12 cm, pore size of 41 μm) and incubated in duplicates for 0, 4, 8, 16, 24, 48, 72, 96 and 120 hours periods in the rumen of three cannulated Bonsmara steers. The residues were then analysed for DM and nitrogen. Parameters to describe the dynamics of ruminal degradability of DM and CP were obtained by fitting the data on the exponential equation P = a + b (1 - e-ct) using NEWAY computer program, where “a” is the rapid degradable fraction, “b” is the slow degradable fraction and “c” is the outflow rate. The in vitro DM and CP degradability of rumen undegradable residue collected after 24 and 48 hour incubation was determined by sequential in vitro digestion in pepsin (abomasal) and pancreatin (small intestine) solutions. DM and CP content differed significantly (P ˂ 0.05). D. cinerea leaves had higher levels of DM and CP content than B. thonningii leaves. DM and CP disappearance increased (P < 0.01) as the incubation period increased. There was no difference (P > 0.05) in soluble fraction ‘a’ and ‘b’ of DM of the two species. The CP components for both fraction ‘a’ and ‘b’ differed significantly (P < 0.01) for CP among the two species. There was significant difference (P < 0.01) in post-ruminal digestibility among the two species. CP digestibility of B. thonningii and D. cinerea leaves was reduced (P < 0.01). In conclusion, B. thonningii and D. cinerea leaves showed significant difference based on their fermentation kinetics and in vitro digestibility, suggesting a good nutritional quality which can be used as protein source for ruminants in dry season and supplement to low-quality diets. / NRF