Disponibilidade e absorção de aminoácidos em bovinos alimentados com diferentes fontes de compostos nitrogenados
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Data
2007-08-01
Autores
Rossi Junior, Paulo
Sampaio, Alexandre Amstalden Moraes [UNESP]
Vieira, Paulo de Figueiredo [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
Objetivou-se estudar o fluxo e a absorção de aminoácidos em bovinos alimentados com dietas isoprotéicas formuladas com diferentes fontes nitrogenadas. As dietas foram fornecidas a bezerros holandeses canulados no abomaso, com 8 meses de idade e peso médio de 187 kg, em um total de 21 animais escolhidos aleatoriamente para formar o grupo que constituiu as repetições experimentais (sete por tratamento). As dietas experimentais foram constituídas de 40% de volumoso e 60% de concentrado. Como volumoso, utilizou-se feno de capim-de-rhodes e, no concentrado, utilizaram-se milho, farelo de algodão, levedura, uréia, melaço e minerais. As dietas diferiram apenas quanto à fonte nitrogenada (farelo de algodão, levedura ou uréia). As quantidades (g/dia) de aminoácidos no abomaso e a composição em aminoácidos da proteína presente no abomaso e nas fezes foram influenciadas pela fonte protéica da dieta. As fontes nitrogenadas não afetaram significativamente a digestão de aminoácidos no intestino. A disponibilidade de aminoácidos no abomaso e a absorção no intestino apresentaram valores inferiores aos descritos na literatura, provavelmente porque, neste trabalho, os animais foram submetidos à restrição de ingestão. As fontes nitrogenadas testadas influenciaram a composição e a disponibilidade de aminoácidos em bovinos.
The objective of this study was to investigate the flow and absorption of amino acids (AA) in steers fed diets supplemented with different protein sources. Twenty-one Holstein steers averaging eight months of age and 187 kg of body weight were used. Animals were fitted with abomasal caanulas and fed diets with a forage to concentrate ratio of 40:60. The experimental diets contained Rhodes grass hay, corn, molasses, minerals, and one of the following protein sources: cottonseed meal, yeast, or urea. Animals were assigned to treatments in a completely randomized design with three protein sources and seven replicates per treatment. Each experimental period lasted 17 days with 10 days for diet adaptation and seven days for sample collection. Samples of abomasal digesta were collected every 28 h while those of feces twice a day during the sampling period. The abomasal flow of AA (g/d) and the AA composition of abomasal and fecal samples were significantly affected by protein source. However, no protein source effect was observed for AA digestibility. The abomasal availability and intestinal absorption of AA were lower than expected probably because animals were feed restricted. It can be concluded that AA availability and composition were affected by the different protein sources fed to steers in this trial.
The objective of this study was to investigate the flow and absorption of amino acids (AA) in steers fed diets supplemented with different protein sources. Twenty-one Holstein steers averaging eight months of age and 187 kg of body weight were used. Animals were fitted with abomasal caanulas and fed diets with a forage to concentrate ratio of 40:60. The experimental diets contained Rhodes grass hay, corn, molasses, minerals, and one of the following protein sources: cottonseed meal, yeast, or urea. Animals were assigned to treatments in a completely randomized design with three protein sources and seven replicates per treatment. Each experimental period lasted 17 days with 10 days for diet adaptation and seven days for sample collection. Samples of abomasal digesta were collected every 28 h while those of feces twice a day during the sampling period. The abomasal flow of AA (g/d) and the AA composition of abomasal and fecal samples were significantly affected by protein source. However, no protein source effect was observed for AA digestibility. The abomasal availability and intestinal absorption of AA were lower than expected probably because animals were feed restricted. It can be concluded that AA availability and composition were affected by the different protein sources fed to steers in this trial.
Descrição
Palavras-chave
Amino acids, availability, cottonseed meal, Digestibility, Yeast, Urea, Aminoácidos, Digestibilidade, disponibilidade, Farelo de algodão, levedura, Uréia
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 36, n. 4, p. 960-967, 2007.