Effects of different additives on chemical composition, fermentation characteristics and aerobic stability of barley silage

Abstract Text: This study was carried out to determine the effect of various additives on chemical composition, fermentation quality, and aerobic stability of barley silage. Youngyang barley was grown at Animal Research Unit, Gyeongsang National University, Jinju, South Korea, and harvested at 31% DM. Approximately 500 kg of barley forage were chopped and divided into 4 piles and applied with one of four treatments which were L. plantarum (LP, 1.2x10³ cfu/g), L. buchneri (LB, 1.2x10³ cfu/g), fermented persimmon extract (FPE, 1% of fresh forage) and essential oil (EO, 1% of fresh forage). Barley forage was ensiled into 10 L bucket silo in quadruplicate for 0, 1, 3, 7, 48 and 100 day periods. The ANOVA followed by Tukey test was performed using SAS 9.3. The concentrations of CP and ether extract were highest (7.23, 3.83% of DM, respectively, P<0.05) in FPE silage ensiled for 100 days, while crude ash, NDF, ADF and hemicellulose concentrations were highest (51.8, 30.0, 21.8% of DM, respectively, P<0.05) in LB silage. The in vitro digestibility of DM was highest in EO silage (62.5%, P<0.05), while in vitro NDF digestibility was highest (P<0.05) in LB (33.7%) and FPE silages (34.5%), respectively. The pH was not affected, but ammonia-N was highest (P<0.05) in EO silage (0.22%), followed by FPE (0.20%), LB (0.17%) and LP (0.13%) silage. The LP silage had highest (P<0.05) lactate but lowest acetate from the early stage of fermentation (3, 7 and 48 d) to the end (100 d), and so happened in the case of lactate to acetate ratio. In contrary, LB silage showed the reverse pattern in lactate and acetate compared to LP silage. Together with acetate (5.17%), LB silage also had highest (P<0.05) propionate concentration (0.42% of DM) and thus resulted in highest aerobic stability (348 h, P<0.05) in this silage. The yeast count was highest (5.25% of DM, P<0.05) in LP silage with concomitant lowest aerobic stability (254 h, P<0.05). The lactic acid bacteria (LAB) were highest (6.45 log₁₀cfu, P<0.05) in EO silage. The mold was not detected in any treatments. In conclusion, LB efficiently improves the aerobic stability, while LP has lowest aerobic stability as well as in vitro digestibility of NDF. On the other hand, FPE and EO substantially improve aerobic stability, preserved protein efficiently as well as improved the in vitro digestibility of DM and NDF.

Keywords: Barley silage, Additives, Aerobic stability, fermentation quality