This work aimed to investigate the effect of broilers age in the digestibility of nutrients in extruded and toasted full fat soybean (EFFS and TFFS) and soybean meal plus oil (SMO), and in the production of digestive pancreatic enzymes. Five digestibility assays were carried out with broilers of one, two, three, four , and six weeks of age. Total collected excreta methodology was applied. The activities of amylase and pancreatic trypsin enzymes increased linearly with the broilers age, as well as the allometric growth of the pancreas. The highest allometric growth ratio occurred in the second week, coincidentally with the period of increasing activity of the digestive enzymes. However, for lipase activity, distinct age affect was found for each feeds. For birds fed on TFFS, the enzyme activity increased linearly with age, while those fed on EFFS, SMO, and concentrate a quadratic effect was observed. The digestibility coefficients for dry matter and ether extract and the soybeans metabolizable energy (ME) varied at different proportions by age. A positive correlation between ether extract digestibility and lipase activity was also observed. The results of corrected apparent and actual metabolizable energy for EFFS presented a quadratic profile in function of age, increasing ME up to the third week and decreasing after this period. However, ME of TFFS, SMO and concentrate was not affected by chicks age. The nutrient digestibility of feedstuffs varies with chicks age, due to the different enzymatic activities.
nutrient digestibility; pancreatic enzyme; processed soybean
