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A series of in vitro investigations was conducted to study the effects that polyphenolic compounds exerted toward rumen cellulolytic micro-organisms. The effect of the complexing of tannins with proteins on the ruminal degradation and intestinal digestibility of protein was also tested. Five polyphenolic compounds of known molecular mass were selected as representative of hydrolysable tannin (tannic acid) or their molecular components (gallic acid and ellagic acid) and components of condensed tannin (catechin and epicatechin). The effects of polyphenolic compounds on the degradation of microcrystalline cellulose (Avicel) and ryegrass and on the formation of gas and VFAs by mixed rumen micro-organisms undergoing rumen-like fermentation (consecutive batch culture, CBC) were studied. On a molar and weight basis, tannic acid was the most inhibitory compound towards cellulose degradation and on the production of VFAs followed by ellagic acid, catechin and epicatechin. Low concentrations (up to 10 mM) of gallic acid caused a significant (P < 0.05) stimulation of cellulolysis, gas and VFA formation. This was probably due to the presence of gallate-degrading bacteria in the rumen. The ability of the ruminal fungus Neocallimastix frontalis to degrade cellulose in two different media, to adhere to cellulose, to utilize glucose and to form colonies from zoospores was assessed, in the presence and absence of polyphenolic compounds. The compounds tested were more inhibitory towards fungi grown in a defined medium rather than in a peptide and rumen fluid-containing medium, presumably due to the interactions between the proteins in the medium and the tested compounds. The adhesion of three fractions of the fungi to cellulose was inhibited by the presence of phenolic compounds in the medium.

Made available in DSpace on 2014-10-09T12:27:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:00Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:43:56Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:02Z (GMT). No. of bitstreams: 1 06780.pdf: 5473344 bytes, checksum: 4eaff43e6879396350a932193c3b14f3 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:27:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:00Z (GMT). No. of bitstreams: 0 / O presente trabalho teve como objetivos realizar um levantamento para identificar a entomofauna associada a rações na cidade São Paulo/SP bem como avaliar o efeito da radiação gama em rações para alimentação de animais domésticos infestadas por pragas. Amostras de 20 lojas Pet Shop de diferentes regiões da cidade São Paulo/SP foram submetidas a triagens de 1 e 45 dias para coleta de insetos com auxilio de aspirador entomológico e peneiras de diferentes granulometrias. As espécies Sitophilus zeamais, Cryptolestes ferrugineus, Lasioderma serricorne e Oryzaephilus sp. apresentaram maior freqüência. Na avaliação dos efeitos da radiação gama utilizamos amostras de grãos de milho, sementes de girassol e mistura para roedores infestadas com insetos adultos das espécies Sitophilus zeamais, Lasioderma serricorne e Plodia interpunctella, após o periodo de 7 a 10 dias foram retirados os insetos e as amostras submetidas a doses crescentes de radiação gama. As espécies Sitophilus zeamais e Lasioderma serricorne foram submetidas as doses de 0,25 a 1,50kGy e a espécie Plodia interpuctella a doses de 0,10 a 2,0kGy. Decorridos 40 dias após irradiação avaliou-se o número de insetos emergidos. Os resultados dos bioensaios com Sitophilus zeamais como com Lasioderma serricorne demostraram que doses apartir de 0,5 kGy foram suficientes para causar letalidade dos ovos e larvas recém emergidas. Os resultados com a Plodia interpunctella a partir de 1,50 kGy, não emergiram insetos adultos, concluindo-se que essas doses foram suficientes para causar letalidade dos ovos e larvas. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:43:56Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:02Z (GMT). No. of bitstreams: 1 06780.pdf: 5473344 bytes, checksum: 4eaff43e6879396350a932193c3b14f3 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:36:06Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:23Z (GMT). No. of bitstreams: 1 11278.pdf: 1430649 bytes, checksum: a436d2f134f4223026499c63265f2730 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP