Digestibility and nutritional value of amino acids from sorghum and soy in various forms in diets for broilers

Abstract

Were used 56 six-month-old Leghorn roosters to determine amino acid digestibility, by the Silbbald method, in eight ingredients (seven birds for each). Differences in amino acid concentrations were detected in the endogenous excretions of fasting birds, previously fed with the various ingredients. The mean true digestibility coefficient of nine essential amino acids was: in sorghum grain, 91.1; in two commercial soybean pastes, 96.6 and 94.8; and in raw soybeans, untreated and subjected to hydrothermal treatment at 0.42, 0.84, 1.26 and 1.68 kg / cm2 for 30 minutes, 85.7, 86.2, 92.3 and 92.2, respectively. The corresponding values ​​for lysine digestibility were: 91.2, 96.6 and 95.0; and 85.5, 87.3, 90.3 and 92.9. In subsequent tests with broilers, diets with three levels of protein (21, 22 and 23%), formulated on the basis of digestible amino acids or total amino acids, were compared. No differences were observed in gain and feed conversion between the diets formulated with both bases or between protein levels, despite moderately high intakes of trypsin inhibitors. Dietary levels of 21% protein, 1.1% lysine and 0.5% methionine were adequate.