Effects of addition of previously fermented juice prepared from alfalfa on fermentation quality and protein degradation of alfalfa silage

Potential effects of previously fermented juice (PFJ) as a silage additive on fermentation quality and protein degradation of alfalfa silage were investigated. The PFJ was made from alfalfa juice which was anaerobically stored for 2 days. All silages were prepared in mini-silos of 100 ml polypropylene centrifuge tubes. Treatments included four variations: (1) nothing added (control); (2) inoculant of lactic acid bacteria (LAB, “Fast Sile”); (3) addition of previously fermented juice with 2 ml/kg fresh matter (FM) (PFJ2); (4) addition of previously fermented juice with 5 ml/kg FM (PFJ5). Results suggest that silage treated with LAB and PFJ, regardless of addition level, had better fermentation quality than the control silage as evidenced by lower pH and NH3-N concentrations, as well as higher lactic acid production (P<0.05) and less protein degradation as suggested by the low NPN production (P<0.05). In addition, the efficiency of PFJ on alfalfa fermentation quality and protein degradation was more than that of LAB, but there were no differences between PFJ2 and PFJ5 on fermentation quality, although PFJ5 resulted in lower (P<0.05) proteolysis. Results indicate that previously fermented alfalfa juice not only enhances fermentation quality, but also inhibits protein degradation of alfalfa silage and is an effective silage additive.