453 resultados para Aditivo


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Biodiesel is a fuel made up by mono-alkyl-esters of long chain fatty acids, derived from vegetable oils or animal fat. This fuel can be used in compression ignition engines for automotive propulsion or energy generation, as a partial or total substitute of fossil diesel fuel. Biodiesel can be processed from different mechanisms. Transesterification is the most common process for obtaining biodiesel, in which an ester compound reacts with an alcohol to form a new ester and a new alcohol. These reactions are normally catalyzed by the addition of an acid or a base. Initially sunflower, castor and soybean oil physicochemical properties are determined according to standard test methods, to evaluate if they had favorable conditions for use as raw material in the transesterification reaction. Sunflower, castor and soybean biodiesel were obtained by the methylic transesterification route in the presence of KOH and presented a yield above 93% m/m. The sunflower/castor and soybean/castor blends were studied with the aim of evaluating the thermal and oxidative stability of the biofuels. The biodiesel and blends were characterized by acid value, iodine value, density, flash point, sulfur content, and content of methanol and esters by gas chromatography (GC). Also studies of thermal and oxidative stability by Thermogravimetry (TG), Differential Scanning Calorimetry High Pressure (P-DSC) and dynamic method exothermic and Rancimat were carried out. Biodiesel sunflower and soybean are presented according to the specifications established by the Resolution ANP no 7/2008. Biodiesel from castor oil, as expected, showed a high density and kinematic viscosity. For the blends studied, the concentration of castor biodiesel to increased the density, kinematic viscosity and flash point. The addition of castor biodiesel as antioxidant in sunflower and soybean biodiesels is promising, for a significant improvement in resistance to autoxidation and therefore on its oxidative stability. The blends showed that compliance with the requirements of the ANP have been included in the range of 20-40%. This form may be used as a partial substitute of fossil diesel

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Os objetivos neste experimento foram avaliar os efeitos da inclusão de extrato de orégano (EO) como aditivo promotor de crescimento nas rações sobre o desempenho, o sistema imune (peso e tamanho da bursa de Fabricius, peso do baço e do timo), as características anatomo-fisiológicas do trato gastrointestinal (altura de vilosidade, profundidade de cripta e suas relações), a microbiologia do ceco e o pH do duodeno e do ceco de frangos de corte. Foram utilizados 1.440 pintos de corte machos Cobb 500, em duas fases de criação (1 a 21 e 1 a 42 dias de idade), distribuídos em delineamento inteiramente casualizado, com seis tratamentos e oito repetições de 30 aves. Utilizou-se ração basal (RB) para as três fases de criação (1 a 21, 22 a 35 e 36 a 42 dias de idade), constituindo os seguintes tratamentos: T1 - RB; T2 - RB com antibiótico (25 ppm de bacitracina de zinco); T3 - RB com 0,025% EO; T4 - RB com 0,050% EO; T5 - RB com 0,075% EO; e T6 -RB com 0,100% EO. Observou-se que os tratamentos não influenciaram o desempenho e os pHs dos conteúdos duodenal e cecal das aves nas duas fases de criação. As variáveis de imunidade e avaliação anatomo-fisiológica do trato gastrointestinal aos 21 dias não apresentaram diferenças. Apenas o peso do baço e a altura de vilosidade aos 42 dias de idade foram influenciados pelos tratamentos. Houve redução no número de bactérias no ceco das aves à medida que se elevou o conteúdo do extrato de orégano nas rações, indicando que houve ação antimicrobiana dos componentes deste extrato. Na condição em que foi realizado o experimento, o uso do extrato de orégano como aditivo promotor de crescimento não ocasionou efeito diferente dos demais tratamentos (antibiótico e testemunha).

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The aim of the study was to evaluate the effects of the inclusion of different levels of turnip cake (TNF) on the chemical composition, digestibility and quality of elephant grass silage. Due to the quality of the oil extracted from the seeds, the turnip is being considered as an important option for the biodiesel industry in Brazil. The turnip cake is obtained from the mechanical pressing of the seeds to produce oil, and it differs from the meal by the content of fat. In the meal the fat is less than 1%, due to the use of solvents for the oil extraction. Experimental silos were used in a completely randomized design, in factorial arrangement 2 x 3 (two types of material and four levels of inclusion). The materials were represented for original material (fresh) and ensiled material, with four levels of inclusion of TNF (0, 3, 6, and 9%). Dry matter (DM), ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), nitrogen indigestible neutral detergent (NIDN), nitrogen indigestible acid detergent (NIDA), ash (MM), lignin (LIG), buffer power (PT), calcium (Ca), phosphorus (P) and in vitro dry matter digestibility (IVDDM) were determined in all materials. In silage, additionally, were determined pH and amoniacal nitrogen (NH3-N). There were effects of inclusion of TNF and the type of material on the DM, CP, ADF, NIDA, P, and MM contents and on IVDDM. The interaction of the two factors was observed to the contents of CP, NDF, ADF, NIDA, Ca and IVDDM. In silage, the DM levels were lower (P < 0.05) than in original material. The values of DM were increased linearly as increased levels of inclusion of TNF. The fibrous components, including NIDN and NIDA, decreased linearly when the TNF increased. In all treatments, values of pH and N-NH3 considered ideal for good silage were observed. The IVDDM was reduced, linearly, with the addition of increasing levels of TNF. A negative correlation (-0.95) between IVDDM and content of EE may explain the tendency of this variable, due to the EE content increased linearly with the addition of TNF. The addition of TNF as an additive in silage of elephant diminished IVDDM. Considering the changes observed in the chemical composition and digestibility of elephant grass silage with TNF as additive, suggests that this should not be included at levels exceeding 3%. On the other hand, the silages with TNF as additive showed appropriate fermentation characteristics.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Incluye Bibliografía

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Pós-graduação em Ciência Animal - FMVA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Compreendendo basicamente o uso dos seguintes materiais: efluente de abatedouro avícola proveniente de operações de abate e lavagem de frangos.

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Pós-graduação em Ciência e Tecnologia Animal - FEIS

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)