Atualização da proteína ideal para frangos de corte: valina e isoleucina

• Autor(a) principal: Tavernari, Fernando de Castro
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1750
• topic: Aminoácidos; Desempenho; Carcaça; Amino acids; Performance; Carcass; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL::EXIGENCIAS NUTRICIONAIS DOS ANIMAIS

Four experiments were carried out at the Department of Animal Science of Federal University of Viçosa to update the profile of the ideal protein for broiler chickens. The first and second experiment evaluated different digestible valine/lysine ratios in the starter (08 to 21 days) and finishing (30 to 43 days) phases. It was used, in both phases, a randomized block experimental design with seven treatments (six different digestible valine/lysine ratios and one control) and eight replicate of 25 and 20 birds (males, COBB) in the starter and finishing phases, respectively. The diets were adequate of requirements except for valine and lysine. To avoid excess lysine in the experimental diets the digestible lysine content was calculated to be about 93% of the requirements. The control diet was adequate in lysine and valine. Feed intake, weight gain, feed conversion and carcass yield in two phases were evaluated. There was no significant effect (P>0.05) of the different ratios in feed intake, however was quadratic effect (P<0.05) on weight gain and feed conversion in both phases. There was no significant effect (P>0.05) on carcass yields evaluated in both phases. The requirement of valine for the carcass parameters is lower than the requirements for performance. The digestible valine/lysine ratios recommended for broiler chickens in the initial phase (08 to 21 days) is 76% and for the final phase (30 to 43 days) is 76%. The third and fourth experiment evaluated different digestible isoleucine/lysine ratios in the starter (07 to 21 days) and finishing (30 to 43 days) phases. It was used, in both phases, a randomized block experimental design with seven treatments (six different digestible isoleucine/lysine ratios and one control) and eight replicate of 25 and 20 birds (males, COBB) in the starter and finishing phases, respectively. The diets were adequate of requirements except for isoleucine and lysine. To avoid excess lysine in the experimental diets the digestible lysine content was calculated to be about 87% and 89% of the requirements in the starter and finishing phases, respectively. The control diet was adequate in lysine and isoleucine. Feed intake, weight gain, feed conversion and carcass yield in two phases were evaluated. There was quadratic effect (P<0.05) of different ratios on feed intake in the finishing phase and over the weight gain and feed conversion in both phases. There was quadratic effect (P<0.05) on breast meat and breast fillet yields in the starter phase, but there was no significant effect (P>0.05) on carcass yield in the finishing phase. The digestible isoleucine/lysine ratios recommended for broiler chickens in the starter phase (07 to 21 days) is 66% and for the finishing phase (30 to 43 days) is 68%.