Effects of reuterin-producing Lactobacillus reuteri strain plus glycerol on the quality and aerobic stability of laboratory sorghum silage

Abstract

Aerobic spoilage of silage is one of the main causes of economic losseses to the livestock industry. The objective of this study was to evaluate the effect of reuterin-producing L. reuteri SO23 plus glycerol on the aerobic stability of laboratory sorghum silage. Chopped sorghum was added with 2% glycerol and inoculated with L. reuteri SO23 and/or a commercial silage additive. Treated forage was packed in laboratory silos and stored for 90 days. Microbial inoculation did not affect the chemical parameters and all silages had low pH values (≤3.63). It was determined that silages inoculated with LAB strains were characterized by higher DM recovery (P<0.001) and aerobic stability (P<0.001), and lower mould and yeast counts (P=0.009). Aerobic spoilage began at day 7 for untreated control silage, and between day 12 and 15 for inoculated silages. Control and treated silages showed some differences in mould counts during the time of exposure to oxygen, but the extent of these differences was dependent on the inoculant applied. In conclusion, inoculation with L. reuteri SO23 plus glycerol improved aerobic stability of sorghum silage, retarded pH increase upon exposure to air, and slowed down the increase of moulds and yeasts populations from day 4 of aerobic exposure. The results also showed that the combination of L. reuteri SO23 and commercial additive is preferable because this combination reduced fermentation losses, mould and yeast counts, and improved silage aerobic stability.