Relação triptofano:lisina em rações para poedeiras leves

• Ano de defesa: 2011
• Autor(a) principal: Calderano, Arele Arlindo
• Orientador(a): Gomes, Paulo Cezar
• Banca de defesa: Rodrigues, Paulo Borges , Cupertino, Edwiney Sebastião , Almeida, Priscila D' Agostini de
• 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: Triptofano; Energia metabolizável; Poedeiras leves
• Palavras-chave em Inglês: Tryptophan; Metabolizable energy; Laying hens
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/1774

Two experiments were carried to determine the ideal ratio of digestible tryptophan:digestible lysine in diets for light laying hens from 24 to 40 and 42 to 58 weeks of age. A total of 240 laying hens Hy-Line W-36 were used in each experiment. The hens were distributed in a completely randomized experimental design with 5 treatments, 8 replicates and 6 hens per experimental unit. When they completed 24 (experiment I) and 42 (experiment II) weeks of age the birds received the experimental treatments that consisted of diets isonutrient, except for levels of digestible tryptophan. In the experiment I the levels of digestible tryptophan used in diets were 0.157; 0.168; 0.179; 0.190 and 0.201%, providing ratios of digestible tryptophan: digestible lysine of 21.5; 23.0; 24.5; 26.0 and 27.5. Was used a suboptimal level of digestible lysine in the diets of 0.730%. In the experiment II the levels of digestible tryptophan used in diets were 0.149; 0.160; 0.171; 0.182 and 0.193%, providing ratios of digestible tryptophan:digestible lysine of 21.5; 23.1; 24.6; 26.2 e 27.8. Was used a suboptimal level of digestible lysine in the diets of 0.694%. In both experiments the following parameters were evaluated: food intake (feed, digestible tryptophan and digestible lysine), egg production, egg weight, egg mass, feed conversion (dozen eggs and egg mass), efficiency of digestible lysine utilization (mass and number of eggs), percentage of egg components, weight gain and nitrogen balance. In the experiment I there was a linear effect on feed intake, digestible tryptophan intake, digestible lysine intake, egg production, egg mass, feed conversion per egg mass, efficiency of lysine utilization per egg mass and weight gain. We also observed a quadratic effect on egg weight. For the efficiency of digestible lysine utilization per egg mass there was best fitted of the data to the LRP model. For the LRP model was obtained smallest sum of squared deviations. The level of digestible tryptophan in diet from which the plateau occurred was 0.184%. This level corresponded to intake of 142 mg/bird/day of digestible tryptophan and the ideal ratio of digestible tryptophan:digestible lysine of 25.2%. In the experiment II was observed linear effect on digestible tryptophan intake. There was quadratic effect on egg production, egg mass, feed conversion per egg mass and efficiency of lysine utilization per egg mass. For feed conversion per egg mass 0.178% was obtained as optimal level. xiii This level corresponded to intake of 158 mg/bird/day of digestible tryptophan and the ideal ratio of digestible tryptophan:digestible lysine of 25.6%. Applying the limit of 95% for the quadratic response was obtained the ratio of 24.3%. The ideal ratio of digestible tryptophan:digestible lysine recommended in diets for light laying hens from 24 to 40 and 42 to 58 week of age are 25.2% and 24,3%, respectively.