Caulim na alimenta??o de poedeiras comerciais no final do ciclo produtivo

• Ano de defesa: 2019
• Autor(a) principal: Reis, T?lio Leite
• Orientador(a): Calixto, Ligia Fatima Lima
• Banca de defesa: Calixto, Ligia Fatima Lima, Curvello, Fernando Augusto, Vieites, Fl?vio Medeiros, Moraes, Jos? Evandro de, Togashi, Cristina Kimie
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Zootecnia
• Departamento: Instituto de Zootecnia
• País: Brasil
• Palavras-chave em Português: Argila; Morfologia intestinal; Qualidade ?ssea
• Palavras-chave em Inglês: Clay; Intestinal morphology; Bone quality
• Área do conhecimento CNPq: Zootecnia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/jspui/5490

The objective of this work was to investigate the inclusion of kaolin levels in the semiheavy laying hens at the end of the productive cycle and its influence on the parameters of performance, egg quality, bone quality, intestinal morphology, gastrointestinal tract weight, of excreta, apparent dry matter digestibility and economic viability. 288 semiheavy chickens were housed, still in the rearing phase (14 weeks). The birds were distributed in a completely randomized design, with six treatments, of eight replications, containing six birds per replicate. When the birds reached the age of 63 weeks of age, the experimental rations were started, which were differentiated by the inclusion of increasing levels of kaolin: Control (without the addition of the additive); T2: inclusion of 1% kaolin in the diet; T3: inclusion of 2% kaolin in the diet; T4: inclusion of 3% kaolin in the diet; T5: inclusion of 4% of kaolin in the diet and T6: inclusion of 5% of kaolin in the diet. The intestinal morphology was evaluated through villus height, crypt depth and villus: crypt ratio; performance was measured by egg production per day (percentage), mean egg weight, feed intake, feed conversion per mass and per dozen eggs produced and the viability of the birds; egg quality, egg mass, Haugh unit, yolk index, yolk pigmentation, yolk and albumen pH, percentage of egg components (shell, albumen and yolk), shell thickness, specific gravity and shell strength. The apparent digestibility of dry matter, mineral matter and levels of calcium, phosphorus and moisture of the excreta was measured, as well as the absolute weight of the organs of the gastrointestinal tract and the bone quality, measured by the Seedor index, breaking resistance and mineral matter tibia. The economic viability of the tested additive was evaluated through the price per kilogram of feed, the price of the feed consumed per day, the cost of the feed for dozens of eggs produced, profitability and cost of the activity. The inclusion of kaolin promoted an improvement in the height of the jejunum, allowing a lower feed intake. There was no significant difference (p>0,05) in egg quality and size of organs of the gastrointestinal tract. The financial analysis revealed that the higher the kaolin addition, the higher the cost of the feed and this did not promote improvement in the economic indexes. The apparent digestibility of the dry matter was reduced, as well as the moisture level of the excreta as the level of kaolin in the diet increased, the mineral matter excretion responded linearly (p <0.05) and retention in quadratic form (p<0,05) to the inclusion of kaolin, and there was no significant difference (p>0,05) for calcium and phosphorus excretion. There was improvement in bone quality (p<0,05) measured in the Seedor index, with no difference (p>0.05) in the other parameters that evaluated this structure.