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Nonenzymatically browned soybean meal as a supplemental protein source for growing ruminants

Ralph Morton Cleale, University of Nebraska - Lincoln

Abstract

Controlled nonenzymatic browning was investigated as a means of protecting soybean meal (SBM) from ruminal proteolysis. Trials were conducted, with in vitro ammonia release as the response criterion, to evaluate factors controlling nonenzymatic browning of SBM. Xylose was a more reactive (P $<$.01) reducing sugar than glucose, fructose and lactose in SBM samples heated at 150 C and at pH 8.5. Ammonia release suppression was greater (P $<$.05) from SBM samples treated with sodium hydroxide (NaOH) to pH 8.5 or 10.0 than from those without NaOH (pH 6.5), and greater (P $<$.05) at pH 10.0 than 8.5. Ammonia release suppression from samples treated with xylose and heat at pH 8.5 was greatest in samples containing 65 to 80% DM, but decreased when samples contained greater than 80% DM. In a trial with duodenally cannulated steers, nonenzymatic browning of SBM (3 mol/mol SBM lysine, pH 8.5, 83% dry matter (DM), heated 30 min at 150 C; XTS-30) increased (P $<$.01) ruminal escape of SBM nitrogen (N) to more than twice that of untreated, commercial SBM (CS) without reducing total tract N digestibility. Para-amino hippuric acid was used to estimate hepatic portal blood flow in lambs in a trial designed to measure differences in net portal absorption of alpha-amino N (AAN) as affected by supplementing N as urea (U), CS or XTS-30. In a lamb growth trial, the relative protein value of XTS-30 was two times that of CS (P $<$.05). In a digestion trial, apparent digestibility of N from XTS-30 and XTS-55 by lambs was lower (P $<$.01) than that of CS. In a steer growth trial, the relative protein value of GTS (3 mol glucose/mol SBM lysine, pH 8.5, 80% DM, heated 30 min at 150 C) was more than twice that of CS (P $<$.05), but not different than the positive control, which was a 50:50 (protein basis) mixture of corn gluten meal and blood meal. In a second digestion trial, apparent digestibility by lambs of N from GTS was lower (P $<$.05) than that from CS. (Abstract shortened with permission of author.)

Subject Area

Livestock

Recommended Citation

Cleale, Ralph Morton, "Nonenzymatically browned soybean meal as a supplemental protein source for growing ruminants" (1986). ETD collection for University of Nebraska-Lincoln. AAI8818612.
https://digitalcommons.unl.edu/dissertations/AAI8818612

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