1775
Effects of lactobacilli and fibrolytic enzymes on chemical composition, ferementation traits, conservation characteristics and in situ digestibility of mixed cereal silage
Growing mixed cereal crops for silage offers benefits in terms of increased yields and enhanced disease resistance. Little information is available regarding the effects of silage additives on the conservation characteristics and nutritional value of mixed cereal crops. This study was to determine the effect of lactic acid-producing bacteria (LAB) and fibrolytic enzymes on chemical composition, conservation characteristics and in situ digestibility of a mixed cereal crop consisting of barley, oats and spring triticale seeded 1:1:1. Forage was harvested at the mid-dough stage, wilted to 33% DM, chopped to 1 cm and either not treated (Control) or inoculated with a mixture of esterase-producing Lactobacillus buchneri, L plantarum and L casei (T1), a mixture of non-esterase-producing L. buchneri, L. plantarum and E. faecium (T2) or T2 plus exogenous enzymes (Rovabio Excel LC, T3). The MIXED procedure of SAS was used for this study with completely randomized design. The fixed factors were bacteria treatment, run and cow for in ensiling, in vitro and in situ trials respectively. After treatment, forage was packed and stored in mini-silos for 90 d, prior to measurement of ensiling characteristics and in vitro and in situ digestibility. Both T1 and T2 silage had higher NDF (P < 0.001) than Control or T3. All inoculants increased populations of LAB (P< 0.01) but, reduced concentrations of water soluble carbohydrate (P <0.01), ammonia (P< 0.001) and pH (P < 0.001) in mixed crop silage. Compared with Control, T1 silage had lower (P< 0.001) whereas T2 and T3 silage had higher (P < 0.001) concentrations of acetic acid and total VFA. Concentration of lactic acid was similar among all silages. All silages had similar DM disappearance and VFA production during 48-h of in vitro ruminal incubation. However, in situ NDF disappearance of T1 silage was higher (P<0.001) than that of Control and T3 silage. Applying esterase-producing Lactobacillus at ensiling to a mixture of barley, oats and spring triticale has potential to improve fermentation traits and enhance the fibre digestibility of silage.
Keywords: Lactobacillus, mixed cereal silage, rumen digestion