Avaliação da qualidade nutricional de genótipos de cana-de-açúcar (Saccharum spp.) e de sua silagem com diferentes aditivos

• Ano de defesa: 2005
• Autor(a) principal: Freitas, Acyr Wanderley de Paula
• Orientador(a): Pereira, José Carlos
• Banca de defesa: Leão, Maria Ignez , Detmann, Edenio , Barbosa, Marcio Henrique Pereira , Fontes, Carlos Augusto de Alencar
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Ruminante; Nutrição animal; Cana-de-açúcar; Silagem
• Palavras-chave em Inglês: Rumen; Animal nutrition; Sugarcane; Silage
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/1675

The experiments were conducted in the Universidade Federal de Viçosa, Animal Science Department with the objectives of evaluating sugarcane genotypes nutritional quality and the influence of different types of additives at the ensiling process of sugarcane on silage nutritional quality and fermentative parameters. A first experiment was conducted in order to evaluete the sugarcane nutritional quality and to select of clones for the feeding of ruminant animals, using the Tocher method. The sugarcane genotypes evaluated were: RB72454, RB835486, SP80-1842, IAC86-2480, RB977512, RB867515, RB935566, RB925342, RB977625, SP79-1011, SP80-1816, SP81-3250 and SP91-1049, harvested at 11 months of age. The discriminatory variables used were: Neutral detergent fiber (NDF); hemicelulose; lignin; NDF to soluble carbohydrate relation; NDF indegradable fraction; NDF degradation rate; and dry matter degradation rate. The most important variables for group discrimination were NDF and DM degradation rate, contributing, each one with 25.64% of the total discrimination power. NDF indegradable fraction presented the least contribution (11.54%) for group discrimination. The variables NDF, NDF indegradable fraction, hemicelulose, DM degradation rate, and NDF degradation rate showed to be effective in the study of sugarcane nutritional divergence. Group III constituted by the clone RB977512 presented the best average values for the evaluated variables, so it can be considered of higher nutritional quality for ruminant feeding. The objective of the second experiment was to evaluate the influence of the microbial inoculant L. plantarum in the doses of 1 x 106, 1,2 x 106 e 1,4 x 106 cfu g-1, soy crop residue (10%), NaOH (3% of DM), residue combined with NaOH, and residue combined with L. plantarum 1 x 106, on the nutritive quality, DM losses, and fermentation parameters. The variety RB855536 harvested at 11 and 13 months was used. The experiment was conducted in factorial outline 2 x 8 (two ages and eight treatments). The results were evaluated by the factor analysis. For the composition and degradation kinetic variables three factors were considered: nutritional quality (NQ), including the variables dry matter (DM), crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin; physiologic maturity (PM), soluble carbohydrate (SC), lignin and NDF undegradable fraction; and fiber carbohydrate degradation velocity (FDV), including kdNDF. For fermentation characteristics variables, the following factors were considered: secondary fermentation and losses (SFL), including DM loss, acetic acid, propionic acid and ethanol concentrations; hydrogen potential (PH); and protein degradation (PD), amoniacal-N concentration. Soy crop residue in sugar cane silage showed to be capable of improving silage nutritional quality and diminishes DM losses and ethanol production. Silages treated with sodium hydroxide reduced ethanol production, but did not improve nutritional quality and were not capable of diminishing dry matter losses. The utilization of inoculants containing L. plantarum was not capable of improving silages nutritional quality or reducing dry matter losses and ethanol production. The objective of the third experiment was to evaluate the influence of L. plantarum 1 x 106 ufc g-1, L. buchneri 5 x 104 ufc g-1, residue (10%), and residue in combination with the two inoculantes on the nutritional quality, DM loss, and fermentation parameters. The variety RB855536 harvested at 15 months of age was used. The experiment was conducted in a completely randomized arrangement with tree repetitions. Although, the addition of the soy crop residue resulted in an increase in final silage pH, the treatments with the residue reduced in 33% silages DM losses and in 60% the level of amoniacal-N in relation to total nitrogen. The use of the inoculantes reduced silage pH when added in association with the soy crop residue, not having a significant effect on the other parameters. Silages presented higher concentrations of fiber components and reduction on DM levels in relation to the original material, before ensiling, in all treatments. The treatments with the residue presented higher (P<0.05) IVDMD then the other treatments. When compared with the material used for ensiling, the decrease in digestibility was higher for the treatments without the residue (24,3% vs. 9,3%). The combination of the soy crop residue with sugarcane for ensiling presented better nutritional quality and lower DM and SC losses, mainly in the form of gases, and consequently, less accumulation of the cell wall components and loss in forage IVDMD. It is not possible to recommend the utilization of the inoculantes L. plantarum and L. buchneri, in sugarcane ensiling, because no improvement was observed on silages chemical composition or fermentation profile.