Coeficiente de digestibilidade verdadeira dos aminoácidos e valores de aminoácidos digestíveis do milho submetido a diferentes temperaturas de secagem e períodos de armazenamento

Abstract

The objective of this experiment was to determine the true digestibility (TD) of amino acids from corn samples submitted to different drying temperatures (room temperature and artificial drying at 80, 100 and 120°C), and different storage periods (0, 60, 120 and 180 days). The TD of amino acids was determined by the forced feeding method using cecectomized adult Leghorn roosters, placed in individual cages. A 4 × 4 factorial arrangement was used (four drying temperatures and four storage periods), in a completely randomized design, with eight replicates. The endogenous amino acids losses were determined with roosters in fasting. A linear reduction occurred for the methionine + cystine digestibility and a quadratic effect was found for methionine, threonine, lysine, tryptophan and phenylalanine, with the increasing of the drying temperature. Higher TD values for methionine, threonine, lysine, tryptophan and phenylalanine were observed at temperature 40, 25, 27, 32 and 40°C, respectively, obtained by regression equation. A linear reduction occurred for the methionine and threonine digestibility with the storage periods. It could be conclusion that the drying temperature and storage periods of corn grains reduce the digestibility of most amino acids. © 2009 Sociedade Brasileira de Zootecnia.