Separating the chemical and microbial factors of oat harvested at two growth stages to determine the main factor on silage fermentation.

ABSTRACT

AIMS: This work evaluated the effects of epiphytic microbiota and chemical components on fermentation quality and microbial community of ensiled oat. METHODS AND RESULTS: Oat harvested at the heading stage (HS) and the milk stage (MS) was sterilized by gamma-ray irradiation and inoculated as the following (1) HS epiphytic microbiota + sterilized HS (H-H); (2) MS epiphytic microbiota + sterilized HS (M-H); (3) MS epiphytic microbiota + sterilized MS (M-M); and (4) HS epiphytic microbiota + sterilized MS (H-M). After 60-day fermentation, silages inoculated with the epiphytic microbiota of HS had higher acetic acid content than those inoculated with MS. Silage made from sterilized MS had lower pH, ammonia nitrogen and butyric acid contents and higher dry matter, water-soluble carbohydrates and lactic acid contents than that made from sterilized HS. The microbial communities of oat silages were similar, and they were mainly Lactobacillus. CONCLUSIONS: The chemical component rather than the epiphytic microbiota at harvest exerted more effects on oat silages. SIGNIFICANCE AND IMPACT OF THE STUDY This work reveals the different effects of chemical and microbial factors on the fermentation of silage, which is instructive for us to produce quality silage.