179. Effects of Incubating Bacillus Paralicheniformis 809 and Bacillus Subtilis 810 on in vitro Nutrient Disappearance of Feedstuffs and Total Mixed Rations Commonly Used in European Dairy Systems.

Abstract This study evaluated the effects of B. paralicheniformis 809 and B. subtilis 810 incubation on in vitro nutrient degradation of European-based feedstuffs, including forage- and concentrate-based, and dairy TMRs. Forty-five forage-based (n = 22), dairy total mixed rations (TMR; n = 10), and concentrate feedstuffs (n = 13) were used in the current experiment. The experimental treatments evaluated herein were a control (no probiotic inoculation; CON) or inoculation of a mixture of a probiotic containing Bacillus paralicheniformis 809 and B. subtilis 810 (3.2 × 109 CFU of the mixture/g; BOVACILLUSTM, Novonesis, Lyngby, Denmark; DFM) into the jar containing the rumen fluid of the non-lactating dairy cows. The calculation of the probiotic dosage to be incubated into each jar was based on a rumen capacity of 70 L and the dose of 3 g of the probiotic mixture/head per day (total dose of 9.6 × 109 CFU/head per day). Additionally, two independent runs were performed herein and within each run, samples were analyzed in triplicates. All analysis were performed using the SAS statistical software (version 9.4; SAS Inst. Inc.; Cary, NC, USA), using the PROC MIXED and the Satterthwaite approximation to determine the denominator df for the test of fixed effects. The statistical model for IVDMD and IVNDFD at 24 and 48 hours included the fixed effects of treatment, feed type (C = concentrate; F = forage; T = TMR), and the resulting interaction. An additional analysis was performed by taking the median NDF value of each feedstuff type and ranking them as LOW (L) or HIGH (H) quality substrate. For all the statistical analysis performed herein, no treatment × feedstuff type (C, F, or T) interactions were observed (P ≥ 0.16); hence, only main treatment effects will be reported herein for both IVDMD and IVNDFD at both 24 and 48 h timepoints. The in vitro 24- and 48-h DMD was increased (P < 0.001) by 3.4 and 1.1%-units, respectively, following the DFM incubation (Table 1). Similarly, incubating the DFM with the substrates also increased (P < 0.0001) the in vitro 24- and 48-h NDFD by 6.3 and 3.3%-units, respectively (Table 1). Lastly, DFM addition increased IVDMD and IVNDFD, regardless of the substrate quality (P < 0.0001; Table 2). These data indicate that the Bacillus-based DFM is a feasible alternative to promote nutrient degradation of different feedstuffs and TMR. For image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.