The effect of cumin essential oil on the fermentation quality, aerobic stability, and in vitro digestibility of vetch-oat silages

Abstract

Objective: This study has been conducted in order to determine the effect of cumin essential oil on the fermentation quality, aerobic stability, in vitro metabolic energy contents and relative feed value of vetch-oat silages. Material and Methods: Vetch and oat were harvested in May and were wilted for approximately 3 hours. Cumin essential oil was added to silages at CMN2:200 mg/kg, CMN3:300 mg/kg and CMN5:500 mg/kg levels, while no addition was made to the control (CON) group. Vetch-oat mixture was placed in plastic bags, and these bags were vacuumed and were stored at 8±2 °C, at laboratory conditions. In the following 70 days after the ensilage, three packages from each group were opened, and silages were analysed in terms of physical, chemical and microbiological analysis. Aerobic stability test was conducted for five days to silages, which were opened at the end of the ensilage period. Moreover, enzyme soluble organic matter (ESOM) amount, metabolic energy (ME) contents, and relative feed value (RFV) were determined. Results: The addition of essential oil prevented crude protein (CP) degradation, and found out to be higher in experimental groups in comparison to the control group (CMN2: %10.04, CMN3: %10.25, CMN5: % 10.25) (P<0.05). The ammonia nitrogen levels (NH3-N) have also decreased depending upon the increase in the amount of the added essential oil (P<0.05). It was also found out that neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose contents were low in CMN3 and CMN5 groups (P<0.05). It was also determined that with the addition of essential oil, the amount of lactic acid bacteria (LAB) increased (P<0.05), and the amount of yeast and mould decreased both at anaerobic and aerobic periods. Conclusion: Cumin essential oil increased the fermentation qualities of vetch-oat silages. Moreover, it affected the relative feed value positively.