Degradability and digestibility of full-fat soybeans treated with different sugar and heat combinations

Two experiments were conducted to study the effects of different combinatio ns of sugars and heating time and temperature on the ruminal undegradable p rotein fraction and DM digestibility of full-fat soybeans. In the first exp eriment, the influence of sugar addition before heating (none, soaked in ei ther a high fructose corn syrup [HFCS] solution, lignosulfonate or molasses ), micronization temperatures (100, 110, 120, and 130 degrees C), and tempe rature holding times (0, 30, 60, and 120 min) was examined in a 4 x 4 x 4 f actorial arrangement of treatments. In the second experiment, the effect of heating in a sugar solution was studied in a 4 x 2 x 4 factorial design wi th four sugar treatments (none, soaked either in fructose, molasses or a hi gh xylose product), two soaking temperatures (100 and 120 degrees C), and f our soaking times (0, 60, 120, and 240 min). In vitro dry matter digestibil ity (IVDMD), in vitro ruminal undegradable protein (RUP), and in sacco RUP were measured. In the first experiment, increased temperatures and heating to 120 min resulted in an increased RUP fraction of full-fat soybeans with no effect on DM digestibility, relative to when no sugar or fructose was ad ded. There was a decrease in digestibility with increased temperature when lignosulfonate or molasses was added and with increased heating time when l ignosulfonate was added. In the second experiment where soaking in sugar an d heating were done simultaneously, lignosulfonate increased the RUP of soy beans without affecting its digestibility but values were numerically lower than when soaking and micronizing were conducted in two different steps as performed in the first experiment.