Made available in DSpace on 2014-06-11T19:30:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-07-03Bitstream added on 2014-06-13T21:00:44Z : No. of bitstreams: 1 rivera_ar_me_jabo.pdf: 341547 bytes, checksum: 35f0260fb3dc1acd91d7c35f7c4333d4 (MD5) / Universidade Estadual Paulista / O trabalho teve como objetivos avaliar o efeito do uso de monensina e de um complexo de leveduras, ácidos graxos poliinsaturados e aminoácidos (LAA) no consumo de matéria seca e nutrientes, na estimativa da digestibilidade ruminal, nos parâmetros de fermentação ruminal (pH, concentração de nitrogênio amoniacal e de ácidos graxos de cadeia curta), na população de protozoários e na produção de metanoo Foram realizados dois experimentos, no primeiro com seis bovinos anelorados, com peso médio de 530 kg, que foram tratados com 5g dia-1 de LAA ou monensina ou caulim usado como controle, adicionados à dieta base composta por feno de Tifton 85 (Cynodon Sppo) e concentrado, em uma relação 80:200 No segundo experimento foram testados os mesmos aditivos, usando a técnica de produção de gases in vitro para estimar a produção de gás metanoo O delineamento experimental usado foi em blocos casualizadoso Entre os resultados houve menor consumo de matéria seca e dos nutrientes (P<O,05) e maior produção de ácido propiônico (P<0,05) efeito da monensinao A digestibilidade da matéria seca e dos nutrientes não foi influenciada pela utilização dos aditivoso O pH e a concentração de nitrogênio amoniacal foram adequadas para o crescimento microbianoo A produção de metano não foi alterada usando aditivos. / The objetives of this work were to evaluate the effect of additives: monensin and yeast cells, insatured fatty acid, aminoacid complex on nutrient intake, nutrient digestibilities, ruminal parameters, protozoa population and methane production. Two experiments were conducted. One experiment, six beef cattle, 530 kg live weight, feeding hay (Cynodon Spp.) and concentrate (porportion 80:20) were used. Monensin or yeast cells, insatured fatty acid, aminoacid complex or caulim (control) were given daily (5g). Two experiment, same additives were used to estimate methane production using the gas production technique. The statistics model was random block. The nutrient intake decreased (P<0.05) and propionic acid increased (P<0.05) using monensin. There were no effect of additives on nutrient digestibilities. Ammonia nitrogen and pH were adequated for microorganisms growth. There were no effect of additives on methane production.

L’oxydation des lipides est un phénomène chimique qui provoque la dégradation des qualités organoleptiques et nutritionnelles des aliments. Cette oxydation dépend de plusieurs paramètres (température, lumière, présence de métaux de transition, présence d’enzymes, état de dispersion des lipides …) qu’il est important de maîtriser notamment au cours du procédé de fabrication du produit alimentaire ou de son stockage. Dans ce contexte, l’oxydation des lipides a été étudiée, à travers la mesure des composés primaires d’oxydation, en phase continue et en émulsion eau-dans-huile. Différentes huiles alimentaires présentant des taux variés en acide α-linolénique (18:3 n-3) ont été choisies. Différentes formulations d’émulsion ont été étudiées (composition de l’interface en polyricinoléate de polyglycérol (PGPR)/monoglycérides distillés, présence de métaux pro-oxydants, d’espèces chélatantes). En revanche, la fraction volumique de phase aqueuse (40%) et le diamètre des gouttelettes d’eau (1 μm) sont maintenus constants. Parallèlement, une méthode de dosage rapide et innovante basée sur la microcalorimétrie différentielle a été mise au point pour un suivi en continu des cinétiques d’oxydation. Pour les 4 huiles végétales étudiées en phase continue et en émulsion, l’oxydabilité est liée à leur teneur en acide α-linolénique, avec la hiérarchie suivante : huile de lin > huile de caméline > huile de colza > huile d'olive. Plus la concentration en molécules pro-oxydantes (sulfate de fer) dans la phase aqueuse est élevée, plus l’oxydation des lipides est importante. L’état de valence du fer et le remplacement du fer par du cuivre n’ont pas d’impact significatif sur la cinétique d'oxydation. En revanche, il est possible de contrôler l’action pro-oxydante du fer II en jouant sur la nature du contre-ion (poids moléculaire, pouvoir chélatant) ou sur la proportion de PGPR utilisée pour stabiliser les émulsions. L’ensemble des résultats obtenus suggère que les tensioactifs lipophiles présents à l’interface eau-huile n’empêchent pas l’interaction des ions pro-oxydants avec les molécules lipidiques de la phase continue mais que leur organisation à l’interface module l’oxydation des lipides. / Oxidation is ubiquitous in lipids and causes degradation of organoleptic and nutritional qualities of foods. Lipid oxidation depends on various parameters (temperature, light, transition metals, lipid dispersion state …) that have to be controlled during food processing and storage. In this context, lipid oxidation was followed by measuring the content of primary oxidation products, for lipids in bulk phase and in water-in-oil emulsions. Different edible oils were chosen for their contents of α-linolenic acid (18: 3 n-3). Emulsions were formulated at varying polyglycerol polyricinoleate (PGPR)/distilled monoglycerides concentration ratios (surfactant ratio), with or without the presence of pro-oxydant metals or chelators. In all experiments, the aqueous volume fraction (40%) and the droplet mean diameter (1 μm) remained constant. Besides this study, an innovative and rapid method based on differential microcalorimetry was developed for monitoring the kinetics of lipid oxidation. The oxidability of the studied oils was related to their content in α-linolenic acid according the following order: linseed oil> camelina oil> rapeseed oil> olive oil. The rate of lipid oxidation increased with the iron sulfate concentration in the water phase. The iron valence or the replacement of iron by copper had no significant impact on the oxidation kinetics. However, both the chemical nature of the counter ion (molecular weight, chelating power) and the proportion of PGPR used to stabilize the emulsions were influential factors. On the whole, our results suggest that surfactants at the water-oil interface do not prevent pro-oxidant species to interact with lipids in the continuous phase but that their organization at the interface is a key parameter for controlling lipid oxidation.

Orientadora: Telma Teresinha Berchielli Moreno / Banca: Alexandre Amstalden Moraes Sampaio / Banca: Simone Gisele de Oliveira / Resumo: O trabalho teve como objetivos avaliar o efeito do uso de monensina e de um complexo de leveduras, ácidos graxos poliinsaturados e aminoácidos (LAA) no consumo de matéria seca e nutrientes, na estimativa da digestibilidade ruminal, nos parâmetros de fermentação ruminal (pH, concentração de nitrogênio amoniacal e de ácidos graxos de cadeia curta), na população de protozoários e na produção de metanoo Foram realizados dois experimentos, no primeiro com seis bovinos anelorados, com peso médio de 530 kg, que foram tratados com 5g dia-1 de LAA ou monensina ou caulim usado como controle, adicionados à dieta base composta por feno de Tifton 85 (Cynodon Sppo) e concentrado, em uma relação 80:200 No segundo experimento foram testados os mesmos aditivos, usando a técnica de produção de gases in vitro para estimar a produção de gás metanoo O delineamento experimental usado foi em blocos casualizadoso Entre os resultados houve menor consumo de matéria seca e dos nutrientes (P<O,05) e maior produção de ácido propiônico (P<0,05) efeito da monensinao A digestibilidade da matéria seca e dos nutrientes não foi influenciada pela utilização dos aditivoso O pH e a concentração de nitrogênio amoniacal foram adequadas para o crescimento microbianoo A produção de metano não foi alterada usando aditivos. / Abstract: The objetives of this work were to evaluate the effect of additives: monensin and yeast cells, insatured fatty acid, aminoacid complex on nutrient intake, nutrient digestibilities, ruminal parameters, protozoa population and methane production. Two experiments were conducted. One experiment, six beef cattle, 530 kg live weight, feeding hay (Cynodon Spp.) and concentrate (porportion 80:20) were used. Monensin or yeast cells, insatured fatty acid, aminoacid complex or caulim (control) were given daily (5g). Two experiment, same additives were used to estimate methane production using the gas production technique. The statistics model was random block. The nutrient intake decreased (P<0.05) and propionic acid increased (P<0.05) using monensin. There were no effect of additives on nutrient digestibilities. Ammonia nitrogen and pH were adequated for microorganisms growth. There were no effect of additives on methane production. / Mestre