Physicochemical characteristics and microbial community succession during oat silage prepared without or with Lactiplantibacillus plantarum or Lentilactobacillus buchneri

Abstract

ABSTRACT This study aimed to investigate the effects of Lactiplantibacillus plantarum ( L. plantarum ) or Lentilactobacillus buchneri ( L. buchneri ) on the fermentation characteristics and microbial community of oat silages in response to additives. The oat was harvested at the milk stage of maturity and was chopped into 30 mm in size. Then, the oat was treated with distilled water (control, CON treatment), L. buchneri , and L. plantarum ; the addition of L. buchneri and L. plantarum was in 1 × 106 colony-forming units/g of fresh matter and stored at room temperature (25°C). Results showed that the addition of L. plantarum inoculations could increase the lactic acid concentrations of oat silages compared with the control, and the addition of L. buchneri could increase the acetic acid concentrations, whereas the addition of L. plantarum could decrease the fiber contents and increase the crude protein content. The Shannon index of bacterial community was markedly ( P < 0.05) lower in the L. buchneri - and L. plantarum -treated oat silages, and the Shannon index of fungal community was significantly ( P < 0.05) higher in L. buchneri - and L. plantarum -treated oat silages compared with the CON treatment for 7 and 10 days of ensiling. From 7 to 90 days of ensiling, Lactobacillus was the dominant genus during the whole fermentation process in the three treatments. The homofermentative L. plantarum regulated the fermentation quality and microbial community by enhancing the Emden–Meyerhoff pathway, phosphoketolase pathway, and pentosephosphate pathway, and the heterofermentative L. buchneri modulated the ensiling performance and microbial community via improving the pentosephosphate pathway. These results suggested that the addition of lactic acid bacteria could improve the ensiling performance by regulating the microbial community in oat silage, and L. plantarum was more beneficial than L. buchneri for enhancing the fermentation quality. IMPORTANCE Ensiled whole-plant oats are an important feedstuff for ruminants in large parts of the world. Oat silage is rich in dietary fibers, minerals, vitamins, and phytochemicals beneficial to animal health. The fermentation of oat silage is a complex biochemical process that includes interactions between various microorganisms. The activity of many microbes in silage may cause an extensive breakdown of nutrition and lead to undesirable fermentation. Moreover, it is difficult to make high-quality oat silage because the number of epiphytic lactic acid bacterium microflora was lower than the requirement. Understanding the complex microbial community during the fermentation process and its relationship with community functions is therefore important in the context of developing improved fermentation biotechnology systems. These results suggested that the addition of Lactobacillus plantarum or Lactobacillus buchneri regulated the ensiling performance and microbial community in oat silage by shaping the metabolic pathways.