Impact of ferulic acid esterase producing lactobacilli and fibrolytic enzymes on conservation characteristics, aerobic stability and fiber degradability of barley silage

(FAE) producing inoculants or non-FAE inoculants in combination with exogenous fibrolytic enzymes (EFE) at ensiling on silage characteristics and nutritive value of whole barley crop (Hordeum vulgare). Barley (330g DM/kg fresh crop) was harvested at early-dough, chopped and allocated to one of the following four treatments: untreated (Control), FAE producing Lactobacillus buchneri mixture inoculants (T1), none-FAE L buchneri mixture inoculants (T2), and T2 plus EFE (T3). Inoculants were applied at 1 x 10(8) colony forming units/gram forage (cfu/g) and EFE at 424 U (xylanase) and 180 U (endoglucanase)/kg fresh weight. Forage was packed into 12 laboratory silos per treatment and ensiled for 7,28 and 90 d. Subsamples at 90 d were used for in vitro, in situ and aerobic stability studies. After 90d of ensiling, all inoculated silages had less (P< 0.001) water soluble carbohydrate, and greater (P< 0.001) DM loss as compared to the Control. For TI and T2, aNDF was greater (P=0.003) than Control and T3 silage. From d 0 to d 7 of ensiling, 16S rRNA copy numbers of L buchneri in Control increased from 6.5 to 8.0 logo copies/g, thereafter remaining stable, whereas it increased from 7.0 to 10.0 logo copies/g in all inoculated silages, reaching similar to 10.5 log(10) copies/g after 28 d of ensiling. At this time, inoculated silages also had a higher (P< 0.001) pH, produced more acetic acid and ethanol, but less (P= 0.01) lactic acid than Control. After 21-d aerobic exposure, all inoculated silages remained stable, but Control silage deteriorated as indicated by a reduction (P<0.001) in lactic acid and an increase (P< 0.001) in pH, and numbers of yeast. The T3 silage had less (P< 0.001) total gas production than other silages in in vitro ruminal fermentation. Compared to Control, the soluble fraction (a) of DM was less (P< 0.001) in Ti and T2, whereas it was greater (P< 0.001) in T3 silage. In situ NDF digestibility of Ti silage was greater (P< 0.01) than that of Control and T3 silage at 24 and 72 h of incubation. Inoculation of whole crop barley silage with inoculants containing FAE or non-FAE producing L buchneri improved ruminal NDF digestibility, but a combination of EFE with a none-FAE L. buchneri reduced NDF degradability. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.