LAUSR

BACKGROUND The influence of epiphytic microbiota and chemical composition on fermentation quality and microbial community of Italian ryegrass silage were evaluated. Italian ryegrass harvested at the filling stage (FS) and the dough stage (DS) was sterilized by gamma-ray irradiation and inoculated as follows: (I) FS epiphytic microbiota + irradiated FS (F-F); (II) FS epiphytic microbiota + irradiated DS (F-D); (III) DS epiphytic microbiota + irradiated DS (D-D); (IV) DS epiphytic microbiota + irradiated FS (D-F). RESULTS After 60 days of ensiling, silage made from irradiated FS had lower pH and ammonia nitrogen (NH3 -N) content, and higher lactic acid (LA) content than that made from irradiated DS. Similarly, silage inoculated with the epiphytic microbiota of DS had lower pH and NH3 -N content, and higher LA content than that inoculated with the epiphytic microbiota of FS. However, LA-type fermentation (lactic acid: acetic acid > 2: 1) was presented at D-F and D-D. The principal co-ordinates analysis showed that the distance between F-F and D-F, and F-D and D-D was closer than other treatments, suggesting that the microbial community of silages made from irradiated FS (or DS) was more similar. CONCLUSION The epiphytic microbiota played a more important role in the fermentation type, while the chemical composition had a great influence on the contents of fermentation end-products. However, chemical composition had a stronger effect on the microbial community of silage than the epiphytic microbiota. This article is protected by copyright. All rights reserved.