Effects of fibrolytic enzymes, molasses and lactic acid bacteria on fermentation quality of mixed silage of corn and hulless-barely straw in the Tibetan Plateau

The objective of present study was to investigate the effect of fibrolytic enzymes, molasses and lactic acid bacteria on fermentation quality of mixed silage of corn and hulless-barely straw in Tibet. The mixed silage was either untreated (control) or treated with fibrolytic enzymes (E, 0.1% fresh weight, FW), molasses (M, 4% FW), Lactobacillus plantarum (Lp, 6 log colony forming unit [cfu]g(-1) FW), E+Lp and M+Lp. Triplicate silos were opened after 15, 30 and 45days of ensiling, and the average ambient temperature during ensiling was about 10 degrees C. Adding fibrolytic enzymes, molasses or L.plantarum alone improved fermentation quality of the mixed silage with lower (P<0.05) pH, NH3-N, acetic acid and butyric acid concentrations as compared to the control, and silage inoculated with L.plantarum showed better fermentation quality than fibrolytic enzymes or molasses treated silages (P<0.05). The concentration of lactic acid in silages treated with combined additives was higher (P<0.05) than silages treated with each of the three additives alone. Addition of fibrolytic enzymes with or without L.plantarum, both decreased (P<0.05) the ratios of neutral detergent fiber to acid detergent lignin (ADL), acid detergent fiber to ADL, hemicellulose to ADL and cellulose to ADL. The present study suggested that application of L.plantarum together with fibrolytic enzymes or molasses to the mixed silage could further improve the mixed silage quality in comparison with using each of the three additives alone.