1777
Effects of lactobacilli and fibrolytic enzymes on ensiling as well as in vitro and in situ digestibility of of barley silage
Lactobacilli-based inoculants have been shown to improve the ensiling and aerobic stability of barley silage and there is evidence that those with esterase activity may improve fibre digestion. This study aimed to compare the effects of esterase-producing lactobacilli-inoculant to non-esterase or exogenous fibrolytic enzymes inoculants on ensiling characteristic and in situ digestibility. Whole barley crop was cut at the mid-dough stage, wilted to 33% DM and chopped to 1 cm. Chopped barley was subject to the following treatments: 1) control (C; sprayed with water) 2), T1 (inoculated with a mixture of esterase-producing L. buchneri, L. plantarum and L. casei), 3) T2 (inoculated with a mixture of non-esterase-producing L. buchneri, L. plantarum, and E. faecium) and T3 (inoculated with T2 plus exogenous enzymes (Rovabio Excel LC)). Forage was ensiled in PVC laboratory silos for 90 d at which point fermentation characteristics as well as in vitro and in situ digestibility were measured. Silages in T1 and T2 treatment had higher NDF concentration (P < 0.01), but lower water soluble carbohydrate content (P < 0.01) than C or T3 silage. Control silage had lower pH and concentrations of acetic acid, total VFA, total bacteria and lactic acid producing bacteria (P < 0.01), but higher levels of lactic acid and lactic acid: acetic acid (P < 0.01) than other silages. Gas production was lower in T3 silage than other treatments (P < 0.01) whereas C silage had a greater (P < 0.01) in vitro total gas production and rate of gas production. In situ NDF digestibility of T1 silage was greater (P < 0.01) than C silage whereas T3 silage had the lowest (P < 0.01) NDF digestibility. Esterase-producing Lactobacillus buchneri improved the ruminal NDF digestibility of barley silage, a response that was not observed if the inoculant lacked esterase activity or if fibrolytic enzymes were applied exogenously to the forage at the time of ensiling.
Keywords: Lactobacillus, barley silage, rumen digestion