LAUSR

Rumen fluid from fistulated steers receiving a high concentrate diet was utilized to examine the impact of polyphenols and saponin with or without a direct fed microbial (DFM) on in vitro fermentation characteristics. Treatments consisted of: Control (no polyphenols, saponin or DFM); 2) Polyphenols (Mixed Tannins = 15 g/hd/d); 3) Saponin (Y. schidigera = 2 g/hd/d); 4) Polyphenols + DFM (DFM = 1E+7 Lactobacillus animalis + 1E+8 Propionibacteria acidilactici cfu/hd/d); and 5) Saponin + DFM. Rumen fluid was collected and combined in equal amounts from 3 rumen fistulated steers and mixed at a 1:1 ratio of artificial saliva to rumen fluid. Fermentation substrate consisted of 0.5 g of the high concentrate diet. Fermentation bottles were capped with an air-tight rubber stopper and incubated in a water bath for 12 and 18h (7 replicates/treatment/time point). After incubation, the total volume of gas produced was measured and a subsample analyzed for N, CH4 and CO2 concentrations. After gas sampling, pH, VFA concentrations, and DMD were determined. In vitro fermentation parameters were analyzed using a mixed effects model repeated measures analysis for a completely randomized block design. Acetic acid was decreased while valeric acid was increased (P < 0.05) by the Saponin + DFM treatment vs. Control. At 12h DMD was greater in Saponin, Saponin + DFM and Polyphenols + DFM (P < 0.001) treatments compared to Control or Polyphenols alone. Polyphenols produced greater amounts of CH4 /DMD than all other treatments (P < 0.01). Microbial protein production and efficiency were greater (P < 0.001), Saponin + DFM compared to other treatments. Other fermentation parameters measured were not impacted by treatments. Under the conditions of this experiment these data suggest combining DFM with Saponin or Polyphenols produces different ruminal effects from when they are fed alone.