Effects of exogenous proteolyticenzyme to improve in vitro degradation of dried distillers grains with solubles forruminants

Document Type

Presentation

Journal/Book Title/Conference

Effects of exogenous proteolyticenzyme to improve in vitro degradation of dried distillers grains with solubles forruminants

Publication Date

2009

Abstract

A series of experiments was conducted to investigate the effects of adding an exogenous proteolytic enzyme (EPE) on the growth performance of beef steers fed growing and finishing diets containing 30% dried distillers grains with solubles (DDGS; Exp. 1), and results corroborated by in vitro ruminal fermentation in continuous cultures (Exp. 2). In Exp. 1, 48 Angus crossbred steers were randomly allotted to 12 pens (4 animals per pen) and assigned to 2 treatments (6 pens per treatment) in a completely randomized design: DDGS TMR (DT) without and with EPE (27 mg of azocasein hydrolyzed/min/kg DM TMR). The addition of EPE during the growing phase increased DMI (P = 0.02), but had no effects on final BW, BW change, ADG, and G:F. Adding EPE during the growing phase decreased NDF digestibility, whereas the digestibility of DM, CP, and ADF was not affected. There was a tendency for both ADG (P = 0.09) and final BW (P = 0.11) to increase during the finishing phase without affecting BW change and G:F. As opposed to the growing phase, EPE increased digestibility (P < 0.04) of DM, CP, NDF, and ADF. In Exp. 2, 4 dietary treatments were assessed in continuous cultures; non-DDGS TMR (NDT) or DT finishing beef steer diet was combined without or with EPE in a 2 × 2 factorial design. The DT was the same diet used as the finishing diet in Exp. 1, and dose rate of EPE was the same in Exp. 1 and 2. Feeding the DT increased total VFA concentration (P = 0.01), which corresponded with a decreased (P < 0.01) pH compared with the NDT diet (5.8 vs. 6.0) regardless of EPE supplementation. Supplementing EPE tended to increase (P = 0.07) the total VFA concentration in both diets, but only increased digestibility of DM, OM, and NDF when added to the DT diet (P < 0.05), leading to tendencies on TMR × enzyme interaction (P < 0.10). Addition of the EPE product assessed in this study resulted in positive responses in Exp. 1 and 2 when added to finishing beef steer diets, and thus it is clear that the use of protease enzyme products may be more effective in high-concentrate diets such as finishing beef steer diets containing DDGS.

Comments

ASAS-CAAV Pacific Rim Conference.

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