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Aims: To investigate the effects of epiphytic microbiota from napiergrass and Sudan grass on ensiling characteristics and microbial community of oat silage. Methods and Results: By γ‐ray irradiation sterilization and microbiota transplantation technology, the sterilized oat was inoculated as follows: (a) aseptic water (STOT), (b) epiphytic bacteria on oat (OTOT), (c) epiphytic bacteria on napiergrass (OTNP) and (d) epiphytic bacteria on Sudan grass (OTSD). STOT remained in the unfermented state based on similar chemical components with fresh oat. Compared with OTOT and OTSD, higher lactic acid content and ratio of lactic acid to acetic acid, and lower pH, acetic acid and ammonia nitrogen contents were observed in OTNP after 60 days of ensiling. At the late stage, Lactobacillus was the most predominant in each group. Lactococcus was eventually replaced by Lactobacillus in OTSD, whereas Lactococcus was found throughout the whole ensiling process in OTNP. Higher abundance of Weissella was observed in OTSD at the early and late stages. The result of co‐occurrence network analysis proved that Lactococcus was pivotal in determining the silage fermentation pattern during ensiling. According to the 16S rRNA gene‐predicted functional profiles, the inoculation of epiphytic microbiota from oat enhanced the metabolism of amino acids, whereas the inoculation of epiphytic microbiota from napiergrass and Sudan grass accelerated the carbohydrate metabolism. Conclusions: The epiphytic microbiota on napiergrass promoted a homo‐fermentative process, whereas the epiphytic microbiota on oat and Sudan grass facilitated a hetero‐fermentative pattern in oat silage, which was closely related to the abundance and metabolism of Lactococcus, Weissella and Lactobacillus. Significance and Impact of the Study: The exogenous microorganisms that promote the carbohydrate metabolism and inhibit the metabolism of amino acids could be a good potential source to improve the silage quality of temperate grass. [ABSTRACT FROM AUTHOR]

The experiment aimed to compare the effects of citric acid residue (CAR) to that of three commonly used short‐chain fatty acids on the fermentation quality, aerobic stability and structural carbohydrate degradation of lucerne ensiled with lactic acid bacteria (LAB) inoculants. Fresh lucerne was ensiled with distilled water (control), LAB inoculant (L), CAR + LAB inoculant (CL), formic acid + LAB inoculant (FL), acetic acid + LAB inoculant (AL) and propanoic acid + LAB inoculant (PL) for 50 days. Chemical composition and microbial populations were determined after ensiling. The residual silages ensiled for 50 days were evaluated for aerobic stability. Compared with control, CL, FL, AL and PL treatments significantly (p < 0.05) decreased pH, ammonia nitrogen (NH3‐N) and butyric acid contents and increased lactic acid, acetic acid and propionic acid contents. Among them, CL silages had the lowest pH, dry matter and water‐soluble carbohydrate (WSC) content, whereas the population of LAB and the lactic acid contents were highest. Besides, CL outperformed in enhancing fibre degradation, CL silages significantly decreased (p < 0.05) neutral detergent fibre, acid detergent fibre, hemicellulose and cellulose contents compared with control and had the highest Flieg's point. All treated‐silages improved the aerobic stability compared with control, of which L improved 32 h, whereas CL, FL, AL and PL improved 46, 20, 46, >64 h, respectively. Applying a combination of CAR and LAB inoculant improved the fermentation quality and structural carbohydrate degradation of lucerne silage and had a similar effect on aerobic stability compared with other three short‐chain fatty acids. The CAR had a comparable effect on enhancing the fermentation quality compared with three short‐chain fatty acids. Thus, the combination of CAR and LAB inoculant might be used as an ideal additive for lucerne silage making with low WSC and high moisture content. [ABSTRACT FROM AUTHOR]

Aims: To explore the microbiological factors that cause the difference in silage fermentation characteristics between temperate gramineous (Italian ryegrass and oat) grass and legume forage. Methods and Results: Through γ‐ray irradiation sterilization and bacterial transplantation technology, the sterilized red clover was inoculated as follows: (i) aseptic water (STRC); (ii) epiphytic bacteria on red clover (RCRC); (iii) epiphytic bacteria on oat (RCOT); and (iv) epiphytic bacteria on Italian ryegrass (RCIR). Red clover was ensiled in laboratory‐scale silos made of vacuum‐packed plastic bags for 1, 3, 7, 14, 30 and 60 days. STRC remained unfermented state based on similar chemical components with fresh red clover. Compared with RCRC and RCIR, higher lactic acid content and ratio of lactic acid to acetic acid, and lower pH, acetic acid and ammonia nitrogen contents were observed in RCOT after 60 days of ensiling. Using next‐generation sequencing, higher abundances of Methylobacterium and Sphingomonas were observed in the epiphytic bacteria on red clover. Pediococcus was dominant in RCRC after 3 days of ensiling. Lactobacillus was the most predominant in each group after 60 days of fermentation. RCRC and RCIR had a more hetero‐fermentative process, while RCOT possessed a more homo‐fermentative pathway. According to the 16S rRNA gene‐predicted functional profiles, the metabolism of amino acids was accelerated by the epiphytic bacteria from red clover. Conclusions: Inoculating the epiphytic bacteria from oat could alter the fermentation characteristics and bacterial compositions of red clover silage. The relative abundance and activity of Methylobacterium, Sphingomonas, Enterobacteriaceae and hetero‐fermentative Lactobacillus in red clover silage could be changed by the epiphytic bacteria on temperate gramineous grass. Significance and Impact of the Study: The exogenous micro‐organisms inhibiting the metabolism of amino acids can be a good potential source to improve the silage quality of legume forage. [ABSTRACT FROM AUTHOR]