The long-term goal of this project was to improve the utilization of fibrous ingredients in swine through the strategic application of enzymes. We hypothesized that supplementation of enzymes to feed ingredients (in this case, distillers’ dried grains with solubles (DDGS)) in liquid form will enhance their capacity to degrade fibrous substrates, will increase the energetic utilization of fibrous feedstuffs and will allow for the utilization of non-traditional feedstuffs. In the first study, we focused on dry diets and aimed to determine if the combination of an enzyme (protease) with a direct-fed microbial could improve performance of pigs. A total of 72 pigs (18 pens with 6 pens per treatment) weighing 25 kg on average were fed diets that were not supplemented, or supplemented with enzymes (xylanase and β-glucanase), or a combination of protease enzyme and a direct fed microbial. No differences were observed for body weight gain, feed intake, feed efficiency, empty gastro-intestinal weights, or cecal and ileal digesta pH, although pigs fed the protease with direct-fed microbial had a numerical improvement of 6.5% in feed efficiency compared to control-fed pigs. In the second experiment, we hypothesized that steeping high fiber ingredients like DDGS with carbohydrase enzymes may improve their feeding value. We investigated growth performance of growing pigs (144 pigs; 24 pens with 6 pigs per pen) fed diets containing DDGS treated with a blend of β-glucanase and xylanase with or without extended steeping. Treating DDGS with a combination of xylanase and β-glucanase with or without steeping resulted in improved feed efficiency compared to the dry control diet without enzymes for the first three weeks suggesting degradation by enzymes of dietary fibrous components that may otherwise limit nutrient utilization in younger pigs. Supplementation with enzymes improved ADG when DDGS were not steeped (water was added to this diet immediately before feeding as a liquid diet), however, steeping appeared to reduce feed intake, resulting in poorer ADG. Pig body weight was 2.9 kg greater for pigs fed non-steeped liquid diets with enzyme compared with pigs fed the steeped liquid diet with enzyme. Liquid steeped diets had concentrations of acetic acid and lactic acid that could be considered suboptimal, indicating poor fermentation. Therefore, the reduction in growth performance and feed intake of pigs fed the steeped liquid diet may have been related to suboptimal fermentation characteristics of DDGS that was added to the feed. Although growth performance of pigs fed DDGS treated with fiber degrading enzymes did not differ from pigs fed non-treated DDGS control, an interesting area of further exploration is the nature and effects of potential metabolites that could be released when DDGS is treated with fiber degrading enzymes under steeped conditions.
Key Findings:
• Supplementation of xylanase and β-glucanase or a combination of protease with direct-fed microbial did not significantly impact growth performance of grower pigs
• Treating DDGS with xylanase and β-glucanase with or without extended steeping improved feed efficiency for the first three weeks suggesting degradation by supplemental enzymes of dietary fibrous components that may otherwise limit nutrient utilization in younger pigs
• Extended steeping of DDGS appeared to reduce feed intake, resulting in poorer ADG, which may have been related to sub-optimal fermentation of the steeped DDGS.
Contact: Eric van Heugten
North Carolina State University
Box 7621
Raleigh, NC 27695-7621
Phone: (919) 513 1116
E-mail: [email protected]
