step three5 vs 6.3dos, n = 9cuatro, N_exp = 37, rsd = 0.05, P = 0.028, a = 6.4%). Where data were few, this impact was partly confirmed as a trend (n = 82 , P = 0.11) when the analysis was conducted within the experiment and with the volatile fatty acid (VFA) concentration used as a covariate. This trend suggested an eventual favorable effect of yeast on the pH of the medium. To go further in the analysis several sub-bases were built to respond to specific issues.

5 were considered (Jouany et al., 1998; Lynch and ), the influence of yeast supplementation was more marked (pH increase was 0.055 vs 0.024) but less significant (5.32 vs 5.26, n = 14, N_exp = 6, rsd = 0.05, P = 0.064, a = 7.1%). Pooling the data of Carro et al. (1992), Zelenak et al. (1994) and Lynch et al. (2002) allowed testing where there was any interaction between pH response and the level of cell wall (CW) in the diet or feed. The pH actually increased for feeds or diets having a higher level of CW, however there was no effect of yeast on pH and no interaction between CW and yeast.

There was no effect of treatment on VFA concentrations or production ( vs , n = 95, N_exp = 36, rsd = 5.0 mM, P = 0.62, a = 5.3%).

Similarly, there was no impression when lactic acidic amount is fixed from the this new VFA quantity, both things being connected

The acetate:propionate molar ratio was slightly decreased, but this effect was not significant (2.99 vs 3.05, n = 98, N_exp = 38, rsd = 0.20, P = 0.131, a = 5.1%). The proportions of the isoacids were not altered by yeast supplementation (6.33 vs 6.06, n = 38, N_exp = 15, rsd = 0.36%, P = 0.31, a = 9.5%).

Also, there appeared to be no influence of yeast supplementation on lactic acid concentration in the medium (0.646 vs 0.667, n = 32, N_exp = 11, rsd = 0.105 mM, P = 0.603, a = 3.1%).

When only the data with pH<5

The molecular hydrogen status did not seem to be altered by yeast. Columbus escort service Effectively CH4 content or production (13.6 vs 13.4, n = 58, N_exp = 23, rsd = 1.3 mM CH₄, P = 0.576, a = 1.7%) and H₂ content or production (0.444 vs 0.440, n = 44, N_exp = 17, rsd = 0.060 mM H₂, P = 0.842, a = 4.6%) were not significantly modified by adding yeast. For CH₄ there was a positive correlation with VFA, however there was no effect of yeast when VFA were considered as a covariate. Globally there was no influence of yeast on NH₃ content or production (154.4 vs 151.0, n = 55, N_exp = 21, rsd = 10.6 mg N-NH₃/L, P = 0.275, a = 7.3%). However, as the experiments measuring NH₃ levels lower than 100 mg N-NH₃/L were selected, there was a significant increase in response to yeast (72.1 vs 57.8, n = 21, N_exp = 7, rsd = 5.9 mg N-NH₃/ L, P = 0.002, a = 0%).

Microbial N production tended to be increased by adding yeast (837.4 vs 791.0, n = 17, N_exp = 8, rsd = 52.1 mg microbial N/d, P = 0.107, a = 11.7%). Also the efficiency of microbial growth tended to be increased by yeast (21.8 vs 20.4, n = 17, N_exp = 8, rsd = 1.48 g microbial N/kg RFOM, P = 0.099, a = 11.8%).The number of protozoa in the medium was unaffected by yeast (4.48 vs 4.53, n = 32, N_exp = 13, rsd = 0.16 log10 protozoa/ml, P = 0.494, a = 6.25%).