Effects of Propionibacterium Strain P5 on In-Vitro Volatile Fatty Acids Production and Digestibility of Fiber and Starch

The objectives of this study were to determine whether Propionibacterium affects in-vitro VFA production and/or increases the digestibility of fiber and starch. A 4 x 4 x 4 factorial arrangement was used. The main factors were feed source, length of fermentation, and level of added Propionibacterium. Fermentations were conducted in batch cultures with Propionibacterium added to the flasks just prior to the addition of rumen inoculum. The total VFA, acetate, and propionate concentrations increased 9, 5, and 18%, respectively with the addition of Propionibacterium. Propionibacterium decreased dry-matter digestibility by 2% and fiber digestibility by 14%. A second study was conducted to examine the effect of pre-hydration and the carrier of the Propionibacterium on in-vitro fermentation. All levels of Propionibacterium were examined again. The acetate and propionate concentrations decreased by 5% when Propionibacterium was autoclaved; however, autoclaving did not increase dry-matter or fiber digestibility when compared to Propionibacterium alone. Propionibacterium increased the total VFA, acetate, and propionate concentrations, and therefore may enhance the performance of ruminant livestock.