2013 Annual Report
1a.Objectives (from AD-416):
Develop rapid techniques for predicting digestible energy in soybean seed and meal.
1b.Approach (from AD-416):
Conduct studies of amino acid digestibility and nitrogen-corrected, true metabolizable energy (TMEn) to be determined using caged, cecectomized Single Comb White Leghorn roosters. Each of the 10 test feed ingredients will be fed to 5 cecectomized roosters. Roosters will be food-deprived for 24 h prior to being tube-fed (i.e., crop intubated) with 30 g of test feed ingredient. A collection tray will be placed under each cage and all excreta will be collected over the subsequent 48 h period. Excreta samples will be freeze-dried, weighed, ground, and analyzed for amino acids (for amino acid digestibility), as well as gross energy and nitrogen for (TMEn), along with samples of each test feed ingredient. True amino acid digestibility and TMEn will be calculated and corrected for endogenous losses of amino acids and energy, respectively, using excreta samples from food-deprived roosters.
A set of 20 soybean mixtures were prepared and soluble sugar analysis was performed using both wet chemistry and near infrared reflectance (NIR) from project 3620-41000-150-02R, Development of Analytical Technology that Measures Soybean Quality Attributes Rapidly, Cost Effectively, and Consistently. Of these 20, 10 mixes were chosen for three model digestibility studies and one rooster feeding study based on total soluble sugar analysis. These analyses were completed by our collaborators. Both the in vitro and in vivo digestibility data showed trends in the availability of certain amino acids. Cysteine and valine were shown to be the least bioavailable, while glutamic acid, arginine, and proline were the most bioavailable.