Effects of storage temperature and ensiling period on fermentation products, aerobic stability and microbial communities of total mixed ration silage

Abstract

To examine how storage temperatures influence ensiling fermentation, aerobic stability and microbial communities of total mixed ration (TMR) silage. Laboratory-scale silos were stored at 5, 15, 25 and 35°C for 10, 30 and 90days. If silage was stored at 5°C, fermentation was weak until day 30, but acceptable lactic acid production was observed on day 90. The ethanol content was higher than the acetic acid content when stored at 15 and 25°C, whereas the ethanol content was lower when stored at 35 than at 25°C. Aerobic deterioration did not occur when silage was exposed to air at the same temperature at which it was stored. Although 10-day silages stored at 5 and 15°C deteriorated when the aerobic stability test was conducted at 25°C, heating was not observed in silages stored at 25 or 35°C or in any 90-day silages regardless of storage temperature. Denaturing gradient gel electrophoresis demonstrated that bands indicative of Lactobacillus plantarum and Lactobacillus delbrueckii were less prominent, while bands indicative of Lactobacillus panis became more distinct in silages stored at high temperatures. Bands of Kluyveromyces marxianus were seen exclusively in silages that were spoiled at 25°C. High ambient temperature enhances acetic acid production in TMR silage. Lactobacillus panis may be associated with changes in the fermentation products due to differences in storage temperature. The role of Lacto.panis in ensiling fermentation and aerobic stability is worth examining.