Klebsiella as an α-tocopherol source facilitating Lactobacillus plantarum fermentation in rice straw silage1

Abstract

Silage serves as the indispensable diet of ruminants, the increasing mechanism of α-tocopherol during silage making is unclear. Rice straw lacks chlorophyll after harvesting the grain, this can eliminate the impact of tocopherols formed by the breakdown of chlorophyll. Here, we explored the α-tocopherol source, its influencing factor, and its relationship with dominant lactic acid bacteria in rice straw silage treated without or with different additives (sodium benzoate, Lactobacillus plantarum, cell wall degrading enzymes, the combination of Lactobacillus plantarum and cell wall degrading enzymes) and vacuum times (5, 8, 11, and 14 s) after ensiling for 42 d. We found that the pathogenic Klebsiella was traced as the source of increased α-tocopherol in rice straw silage. The residue air in the silo, pH value, and additive variety had impacts on Klebsiella activity, which was strongly active at levels of residue air in the silo and pH that were high. As an acidic niche creator, Lactobacillus plantarum was more effective than sodium benzoate in restraining Klebsiella. Despite having a low acidity tolerance, Klebsiella was still present in rice straw silage treated with L. plantarum. The relationship between Klebsiella and L. plantarum was that Klebsiella could afford α-tocopherol to the multiplication of L. plantarum and residue capsular polysaccharide protected Klebsiella from escaping the extinction in rice straw silage.