212 The Effects of Propionibacterium Acidipropionici P169 in an in Vitro Ruminal Acidosis Model

• Published in: Journal of animal science 2022-04, Vol.100 (Supplement_2), p.101-102
• Main Authors: McNelis, Jenna, Gaffney, Bree, Linder, Haley, Buessing, Zachary, Earing, Jennifer E, Shike, Daniel W, Bernardeau, Marion, McCann, Joshua C
• Format: Article
• Language: English
• ISSN: 0021-8812; 1525-3163
• DOI: 10.1093/jas/skac064.169

The objective was to evaluate the effect of Propionibacterium acidipropionici P169 (PA) concentration on fermentation characteristics in a ruminal acidosis in vitro model. Ruminal acidosis is a common metabolic disorder in feedlot cattle characterized by a low rumen pH. The experiment included 5 treatments in a completely randomized design. Treatments included a negative control (NCON), 5 × 105 colony forming units (CFU) PA (PA5), 5 × 106 CFU PA (PA6), 5 × 107 CFU PA (PA7), and a positive control with greater forage inclusion (PCON). Flasks for NCON, PA5, PA6, and PA7 contained 8.75 g of substrate (70% corn, 15% DDG, 15% silage) while substrate for PCON flasks contain additional silage (40% corn, 15% DDG, 45% silage). Treatments were run in duplicate and the experiment was replicated 3 times. All flasks included 175 mL of inoculum (4 McDougall’s buffer:1 rumen fluid). Flasks were incubated at 39◦C for 36 hours and sample aliquots were collected every 4 hours. The MIXED procedure of SAS 9.4 was used for statistical analysis with a repeated measures analysis. A treatment by hour interaction (P < 0.01) was observed for pH; at hour 8, PCON was the least and PA5 was the greatest. From 20 to 36 h, PCON had the greatest pH. There was no treatment by hour interaction (P = 0.99) observed for redox potential. However, treatment affected (P < 0.01) redox potential with PCON being greater than PA6, PA7, and NCON, with PA5 being intermediate. In vitro dry matter disappearance (IVDMD) tended (P = 0.09) to be affected by treatment; PA5, PA6, and PA7 were greater than PCON. In conclusion, Propionibacterium acidipropionici P169 concentrations affected IVDMD, pH, and redox in a ruminal acidosis in vitro model.