|Holtshausen, Lucia - UNIV.OF STELLENBOSCH|
|Hall, Mary Beth|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2006
Publication Date: July 10, 2006
Citation: Holtshausen, L., Hall, M. 2006. Microbial yield and fiber digestion from sucrose, starch, pectin and bermudagrass fiber fermentation [abstract]. Journal of Dairy Science. 89:(Suppl. 1):88. Technical Abstract: Effect of nonfiber carbohydrates (NFC: sucrose, starch and pectin) fermented with isolated bermudagrass neutral detergent residue (iNDF) on microbial product yield and neutral detergent fiber (NDF) digestion was examined. iNDF with three concentrations of individual NFC (~40 to 120 hexose equivalents; HE) were fermented in six 24 h anaerobic batch culture fermentations with Goering & Van Soest medium and rumen inoculum in 50 ml tubes fitted with gas release valves. Fermentation tubes were destructively sampled every 4 hours and analyzed for microbial glycogen (GLY), organic acids, microbial crude protein (MCP), and residual NDF. Differences among NFC treatments at their maxima with NFC expressed on an HE basis were evaluated by heterogeneity of regression analysis. Significance was declared at P < 0.05. The linear increase in maximum GLY per NFC HE was similar for sucrose and pectin, but their intercept values were numerically different and that for sucrose dwarfed the calculated increase per HE. Yield of total volatile fatty acids (VFA) per NFC HE at 24 h was similar among individual NFC. As NFC HE increased, the proportion of residual NDF at 24 h differed among pectin (less digestion), starch (almost no difference) and sucrose (more digestion). The pattern of MCP yield with increasing NFC HE was quadratic and similar among NFC. The NFC differed in fermentation product yield and effects on NDF fermentation. It is not warranted to regard the various NFC as a uniform entity in ruminant nutrition.