Forages Levels of Glycerin Regression Equations R2 p-value 0% 30% 50% 70% Concentration of Acetate(µmol mL-1) Elephant grass 26.51b 26.6b 28.60a 24.69b Ŷ =27.084+0.012x 0.01 0.8073 Sugar cane 24.89b 22.26b 23.00b 21.37b Ŷ =24.543+0.044x 0.43 0.0206 Corn silage 37.72a 30.27a 25.76b 22.11b Ŷ =37.399+0.224x 0.90 <.0001 Brachiaria grass 12.60c 10.26c 5.10c 35.93a Ŷ =14.023+0.788x-0.015x2 0.79 0.0013 Concentration of Propionate (µmol mL-1) Elephant grass 11.76d 22.13b 27.79a 18.56b Ŷ =11.255-0.675x-0.007x2 0.48 0.0474 Sugar cane 22.27b 25.62a 25.14b 27.77a Ŷ =22.546-0.070x 0.45 0.0175 Corn silage 19.63c 24.22a 33.17a 36.42a Ŷ =18.825-0.254x 0.79 0.0001 Brachiaria grass 35.37a 25.44a 23.34c 39.24a Ŷ =30.149-0.018x 0.01 0.8279 Concentration of Butyrate (µmol mL-1) Elephant grass 3.343a 5.42a 5.80a 4.16a Ŷ =3.298-0.125x-0.001x2 0.52 0.0198 Sugar cane 10.07b 11.61b 11.27c 10.95c Ŷ =10.535-0.011x 0.05 0.4869 Corn silage 12.41a 9.95b 12.72b 13.52b Ŷ =11.335-0.021x 0.11 0.2914 Brachiaria grass 16.61c 22.24c 28.10d 32.83d Ŷ =16.139-0.234x 0.94 <.0001
*Means in the same column with different letters differ statistically by the Tukey test at 5% probability.
Table 3: Mean values, probability (p-value) and regression equations illustrating the effects on production of volatile fatty acids (VFAs) when different levels of glycerin.