RESEARCH

Published Data

Abstract #86, presented at the American Dairy Science Association / ASAS / CSAS Joint Annual Meeting, July 24-28, 2005

07/2005

Effects of soy gum application to soybean meal on protein degradation by ruminal microbes and intestinal protein digestion.

M.D. Stern - University of Minnesota, St. Paul
T.K. Miller-Webster - Rumen Fermentation Profiling Laboratory, West Virginia
W.H. Hoover - Rumen Fermentation Profiling Laboratory, West Virginia
Ruiz Moreno - University of Minnesota, St. Paul
C.A. Macgregor - Grain States Soya, Inc., West Point, NE.

In a preliminary in situ study, mechanical-extracted (ME) soybean meal (SBM) #1 with fresh soy gums (MEC1G) was incubated for 16 h in the rumen of a cow that was 50 days in milk (DIM) and producing 36 kg milk. Rumen undegraded protein (RUP) was 73.3%. In a second in situ study, ME SBM #1 (MEC1) and MEC1G were incubated for 16 h in the rumen of a cow that was 200 DIM and producing 27.2 kg of milk. RUP was 58.0% for MEC1 and 62.1% for MEC1G, indicating that application of fresh soy gums to ME SBM increased RUP.

Two subsequent experiments were conducted. In Experiment 1, eight diets containing 17% CP were examined in continuous culture fermenters to determine RUP. In each diet, 28% of the CP was provided by one of the following products: solvent-extracted (SE) SBM (SOL), ME SBM #1 (MEC1), ME SMB #1 with fresh soy gums (MEC1G), ME SBM #2 (MEC2), ME SBM #3 (MEC3), ME SMB extruded (MECE), SE SBM heat treated (SOLH), SE SBM nonenzymatically browned (SOLNEB). RUP was 30.9, 33.0, 37.6, 32.1, 30.1, 34.3, 32.0 and 31.5% for SOL, MEC1, MEC1G, MEC2, MEC3, MECE, SOLH and SOLNEB diets, respectively. Diet MEC1G had the numerically highest RUP and was different (P<0.10) compared with the SOL, MEC2, MEC3, SOLH, and SOLNEB diets. Results indicate that application of fresh soy gums onto ME SBM can increase RUP.

In Experiment 2, a 3-step in situ/in vitro procedure was used to estimate intestinal CP digestion (ID) for seven SBM products. ID was 67.5, 83.8, 78.9, 75.7, 76.5, 65.4 and 57.7% for SOL, MEC1G, MEC2, MEC3, MECE, SOLH and SOLNEB, respectively. Intestinally absorbable dietary protein (IADP), calculated as RUP x ID was 15.7, 41.3, 33.2, 25.2, 29.3, 34.2 and 39.4% for SOL, MEC1G, MEC2, MEC3, MECE, SOLH and SOLNEB, respectively. ID ranged from 57.7 (SOLNEB) to 83.8% (MEC1G) indicating that processing can overprotect protein from digestion in the intestine.

(New-process Soy Best® with gums is MEC1G; old-process Soy Best without gums is MEC1)
(Journal of Dairy Science, 2005, Volume 83, Supplement 1, Abstract #86, page 90)

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