Procedimentos metodológicos para isolamento in situ de componentes fibrosos indigestíveis em ovinos

• Ano de defesa: 2012
• Autor(a) principal: Alcântara, Pedro Henrique Rezende de
• Orientador(a): Veloso, Cristina Mattos
• Banca de defesa: Espeschit, Claudio José Borela , Marcondes, Marcos Inácio , Valadares, Rilene Ferreira Diniz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Fisiologia; Nutrição; Produção e reprodução de ruminantes
• Palavras-chave em Inglês: Physiology, Nutrition; Production and reproduction of ruminants
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/5756

This dissertation was prepared from data generated in two experiments with procedures for the in situ isolation of indigestible neutral detergent fiber (iNDF) and indigestible acid detergent fiber (iADF) using sheep. The first experiment aimed to determine the in situ incubation time needed for the isolation of iNDF, and investigate the occurrence of mineral contamination in long term incubations in sheep. Samples concentrates, roughages and faeces were used. All samples were ground through in a cutting mill utilizing sieve with pores of 2mm diameter. Subsequently, the samples were placed in 4 x 5 cm non-woven textile fabric (NWT - 100g / m²) bags at the rate of 20 mg of dry matter (DM) / cm ² of exposed area and incubated in the rumen of four male sheep. This procedure was repeated four times, and incubated at every period groups among animals. The following incubation times were used: 0, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240 and 312 hours. After the bags had been removed, the contents of neutral detergent fiber (NDF) and neutral detergent insoluble ash (NDIA) of the residues were analyzed. The NDF degradation profiles were interpreted independently for each material by a non-linear logistic model. The profiles of availability of mineral associated with undegraded NDF were interpreted by a asymptotic model of the first order. Incubation times in sheep of 168 hours are recommended for isolation of NDFi. The content of mineral associated with undegraded NDF stabilized on average 28,9 hours after incubation, showing that samples were not contaminated by mineral, beyond that naturally associated with NDF. In the second experiment, the objective was to evaluate the influence of concentrate level in the diet on the estimates of roughages iNDF and iADF, and, incubation time needed for the in situ isolation of these fractions in sheep. The following forages were used for in situ procedures: in natura sugarcane, Tifton 85 hay, corn straw and corn silage. The samples processing and packaging were carried out following the procedures used in the first experiment. The treatments consisted on diets with different roughage (R): concentrate (C) proportions: 100V: 0C; 80V: 20C, 60V: 40C, 40F: 60C. Treatments were assigned to four male sheep breed, rumen using a Latin square design 4 x 4. The same incubation times used in the first experiment were applied in this experiment. After removal of the bags, they had their NDF and ADF contents analyzed sequentially. The degradation profiles were initially interpreted individually for each forage in each treatment using a non-linear logistic model. For each incubated roughage, the adjusted models were compared to check the effect of treatments on the indigestible fractions (iNDF and iADF) estimates and the fiber degradation rate. It was observed treatment effect (P <0.05) on the iNDFi and iADF estimates for in natura sugarcane and corn silage. It was observed influence of the treatments (P <0.05) on the degradation rates of NDF and ADF to the four roughages It is recommended that for in situ procedures using sheep fed up to 20% concentrate, incubations times of 120 and 144 hours be used for isolation of iNDF and iADF, respectively.