Authors : O. Rosendo , D. B. Bates , L. R. McDowell , C. R. Staples , R McMahon and N. S. Wilkinson
Abstract: The objectives of these studies were 1) to determine if supplemental biotin would overcome the negative effect of low pH on extent of in vitro NDF digestibility (ENDFD) and 2) to measure biotin availability for ruminal microorganisms to degrade forage fiber in media pH of 6.7 and 5.3. In vitro 24-h batch culture incubations were utilized in two experiments. In the first study, the effect of medium pH (6.9, 6.7 and 5.5) on ENDFD of corn silage after 24 h of fermentation was tested. In the second study, only artificial saliva for initial medium pH of 5.3 or 6.7 was used to carry out incubations of alfalfa hay, bermudagrass hay and corn silage. Biotin was added at 0, 10, or 20 ?g tube-1. Biotin (measured as avidin-binding substances for tubes without added biotin) concentration in media increased from 0 to 24 h incubations by 25 and 104% for pH 6.7 (7.9 to 9.9 nM) and 5.3 (9.3 to 19.0 nM), respectively. The ENDFD of the alfalfa and bermudagrass hay were markedly reduced by the lower media pH but did not change with biotin addition. For corn silage, the addition of 20 ?g of biotin depressed ENDFD when the pH was 5.3. Biotin was less utilized at pH 5.3 likely due to a decrease in the growth of cellulolytic microbes. Supplemental biotin added to the fermentation media did not improve ruminal fiber digestibility or minimize the depression on forage fiber digestibility caused by low pH (pH 5.3).
O. Rosendo , D. B. Bates , L. R. McDowell , C. R. Staples , R McMahon and N. S. Wilkinson , 2003. Availability and Ability of Biotin for Promoting Forage Fiber in vitro Ruminal Digestibility . Journal of Animal and Veterinary Advances, 2: 350-357.