## 4 Discussion  
Similar to the previous studies [3; 10; 11], CP, EE, CA, NDF, ADF, and HEMI concentrations of SB increased by more extended cultivation stage, while DM concentration of SB was reported to decrease. As shown in Figure 1, the roots are more developed by the cultivation stages. Generally, these roots in the hydroponic cultivation system have a higher water-holding capacity than the stalk and leaves of SB, which could support the decreased DM concentration in the present study by cultivation stages. The NDSC concentrations of sprouted barley at 0 to 8 days were rapidly decreased by 30%, which might represent the use of energy sources during germination [1; 2; 3]. These explanations also can support the increased CP, EE, CA, NDF, ADF, and HEMI concentrations of sprouted barley by the cultivation stages. Meanwhile, an increase in the cultivation stage produced more green fodder carpets (roots) containing structural carbohydrates, such as NDF, ADF, and HEMI. The concentrations of NDF, ADF, and HEMI rapidly increased at 8 days of the cultivation \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Cultivation Stage, Days**} & \multicolumn{2}{c}{**Contrast**} \\ \cline{2-7}  & **0** & **4** & **8** & **Linear** & **Quadratic** \\ \hline \hline In vitro digestibility, \% DM & & & & & & \\ DM & 34.9  & 65.0  & 56.2  & 1.268 & 0.126 & \textless{}0.001 \\ NDF & 70.1  & 77.0  & 74.2  & 2.014 & 0.286 & 0.005 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Effects of cultivation stages on in vitro rumen digestibility and fermentation characteristics of sprouted barley incubated for 48 h in rumen buffer. [ENDFOOTNOTE] \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & \multicolumn{2}{c}{**Cultivation Stage, Days**} & \multicolumn{2}{c}{**Contrast**} \\ \cline{2-7}  & **0** & **4** & **8** & **Linear** & **Quadratic** \\ \hline \hline DM degradation kinetics & & & & & \\ A, mL/g of DM & 12.2  & 38.4  & 25.9  & 1.228 & 0.793 & \textless{}0.001 \\ B, mL/g of DM & 20.0  & 30.1  & 3.026 & 0.739 & 0.001 \\ A + B, mL/g of DM & 32.2  & 75.5  & 56.0  & 3.471 & 0.943 & \textless{}0.001 \\ C, \%h & 0.28  & 0.05  & 0.006 & 0.010 & 0.058 \\ L, h & 0.00  & 22.5  & 23.0  & 0.185  & 0.185  & 0.185  & 0.185  & 0.185 & \textless{}0.001 & 0.358 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Effects of cultivation stages on dry matter and neutral detergent fiber degradation kinetics of sprouted barley incubated for 48 h in rumen buffer.[ENDFOOTNOTE]stage. From 0 to 8 days of cultivation stages, the increased concentrations of NDF, ADF, and HEMI were 24.7, 14.5, and 10.2%, respectively. The DM, CP, EE, NDF, and ADF concentrations of SB in the present study differed compared to previous studies [2; 9; 10; 11]. These results might be due to the hybrid and cultivation stage differences. The rumen pH decreased in all cultivation stages of SB over incubation hours, which was supported by an increase in total VFA concentration [21]. In general, cultivated SB at 4 days and 8 days presented high total VFA and ammonia-N concentrations in the early hour of incubation (4 h) than cultivated SB at 0 day. It could occur because the germination changed the starch and protein into free sugar and amino acid [1; 2; 22] that degraded faster into VFA and ammonia-N, respectively [21]. However, after 4 h of incubation, the barley grain presented the highest total VFA concentration in the rumen. Soluble carbohydrate is higher in the grain form than sprouted form [2; 3; 10], which was the main reason for this result. In general, rumen pH in SB cultivated at 8 day was lower than in SB cultivated at 4 day. Cultivated SB at 4 day had a lower structural carbohydrate than cultivated SB at 8 day (Table 1), which could decrease the digestibility (Table 3) and produce numerically lower VFA concentration, and then resulted in higher pH. Acetate concentration of SB in the rumen decreased through the hour of incubation without any influence by the cultivation stage.