1077
Gas production and volatile fatty acids of corn stover silage added with yeast culture and fermented apple pomace
Silage is a forage conservation method based on fermentation of carbohydrates to produce lactic acid under anaerobic conditions. Solid state fermentation (SSF) is a process of microbiological growth on solid materials under aerobic conditions. With the objective of improving the nutritional value of corn stover through the combination of SSF and silage, three treatments were driven during 28 d using 48 plastic bags as a microsilos each with 2 kg of: (T1) corn stover alone; (T2) corn stover + yeast culture produced by SSF (10% as feed basis) and (T3) corn stover + fermented apple pomace produced by SSF (69% as feed basis). Treatments were added with water to obtain 35% of DM during the ensilage. Gas production (GP) and volatile fatty acids (VFA´s) were determined in the samples obtained on 14d of the ensilage, following 96 h incubation in buffered rumen fluid using the in vitro fermentation technique. Data were analyzed by PROC GLM of SAS. Results are shown in Table 1. The addition of yeast culture and apple pomace increased GP volume (P<0.01) with values of: 58.17±0.69, 63.57±0.69 and 85.96±0.69 ml*0.2g-1 MS of T1, T2 and T3, respectively. VFA´s differed between treatments (P<0.01). Acetate-propionate ratio increased from 1.8:1 to 2.4:1 (P<0.05) during the in vitro fermentation. Results may be derived from a change in rumen fermentation. It was conclude that the addition of fermented apple pomace or yeast culture improve GP and VFA´s parameters of corn stover silage.
Table 1. Parameters of gas production and volatile fatty acids, determined in the samples obtained on 14d of the ensilage, following 96h incubation in buffered rumen fluid using the in vitro fermentation technique.
Evaluated Variables |
T1 |
T2 |
T3 |
Total Gas Volume (ml*0.2g-1 MS) |
58.17 ± 0.69c |
63.57 ± 0.69b |
85.96 ± 0.69a |
Parameter A (ml*0.2g-1 MS) |
30.05±1.30b |
30.21±1.30b |
39.42±1.30a |
Parameter B (h) |
3.46± 0.07a |
3.03± 0.07b |
2.55± 0.07c |
Parameter C (mL/h) |
0.026±0.00b |
0.028±0.00a |
0.028±0.00a |
Acetic Acid (mM/mL) |
103.06±0.09c |
114.06±0.09b |
120.26±0.09a |
Propionic Acid (mM/mL) |
43.33±0.07c |
46.70±0.07b |
48.59±0.07a |
Butiric Acid (mM/mL) |
16.12±0.06c |
17.60±0.06b |
18.16±0.06a |
a, b, c,Means with literal different between columns indicate statistical difference ( P< 0.05 )Parameter A = asymptote of gas production. Parameter B = average time of gas production after incubation. Parameter C = constant determining the change of profile
Keywords: Yeast Culture, Silage, Corn Stover