Application of Different Types of Lactic Acid Bacteria Inoculant on Ensiled Rice Straw; Effects on Silage Quality, Rumen Fermentation, Methane Production and Microbial Population

Bacterial inoculants are known to improve quality of silage. The objectives of the present study were to evaluate the effects of different types of lactic acid bacteria (LAB; L. plantarum, L. salivarius, L. reuteri, L. brevis and S. bovis) inoculation (106 g-1 DM) on rice straw silage quality and to examine these effects on ruminal fermentation characteristics, digestibility and microbial populations in an in vitro condition. Inoculated rice straw was ensiled for 15 and 30 days. For in vitro study, rumen liquor was obtained from two rumen fistulated mature cows fed on mixed forage and concentrate at 60:40 ratio twice daily. Inoculation of LAB improved (P0.05) the rice straw silage quality such as increased dry matter and crude protein contents, decreased pH and butyric acid, and increased propionic acid and LAB contents especially after 30 days of ensiling. Results from in vitro study revealed that addition of LAB to the rice straw silage improved fermentation characteristics such as increased total volatile fatty acids and dry matter digestibility (P0.05). LAB treatments also decreased methane production and methane/total gas ratio after 15 and 30 days of ensiling. From the rumen microbial population perspective, cellulolytic, and fungal zoospores were enhanced while protozoa and methanogens were decreased by the LAB treatments. Based on these results, it could be concluded that inoculating rice straw silage with LAB (especially for L. plantarum and S. bovis) improved silage quality, rumen fermentation parameters and microbial populations in vitro. However, in vivo studies need to confirm those effects.