Fermentation quality of forage oat (Avena sativa L.) silages treated with pre-fermented juices, sorbic acid, glucose and encapsulated-glucose

This experiment was carried out to evaluate the effects of adding encapsulated-glucose, glucose, sorbic acid or pre-fermented juice of epiphytic lactic acid bacteria (FJLB) on the fermentation characteristics and residual mono-and disaccharides compositions of forage oat silages. The additive treatments were as follows: (1) control (no addition), (2) encapsulated-glucose addition at 0.5% as glucose, (3) glucose addition at 1%, (4) sorbic acid addition at 0.1%, (5) FJLB addition at a theoretical application rate of 2.67 × 10 ⁵CFU/g, on the fresh weight basis of forage oat, respectively. Based on the results, although control and encapsulated-glucose had higher contents of BA and AN, the fermentation in all silages was clearly dominated by LAB. Glucose addition improved well the forage oat fermentation quality, however, the utilization efficiency of WSC was lower than that of both sorbic acid and FJLB additions. Sorbic acid addition showed the lowest contents of ethanol, AA, VFAs and AN, and the highest contents of residual fructose and total mono-and disaccharides as well as the highest LA/AA value with significantly higher LA content. These indicated that sorbic acid addition not only inhibited the activity of clostridial and other undesirable bacteria but also stimulated homofermentative LAB activity. These decreased the loss of mono-and disaccharides and greatly increased the utilization efficiency of fermentable substrates by epiphytic LAB. FJLB addition had the lowest pH value and the highest LA content among all additive treatments, and showed the most intensive LA fermentation. This also corresponded well with the observation that FJLB had a higher residual mono-and disaccharides than the other additive treatments except for sorbic acid addition.