A meta-analysis on the influence of essential oils on chemical composition and fermentative quality of silage

Abstract

Essential oils are plant secondary metabolites that have potential as antimicrobial agents. The use of essential oils as silage additives is expected to maintain feed quality and prevent the growth of spoilage microbes during ensiling. This meta-analysis study aimed to determine the effect of levels of essential oils as silage additives on chemical composition and fermentation quality during ensiling. A total of 11 journal articles consisting of 17 studies and 73 data points were tabulated with related parameters about the chemical composition, fermentation quality, and microbial analysis. The results of the analysis indicate that increasing the levels of essential oils linearly increase (p<0.01) certain chemical compositions, such as crude protein, ether extract, and water-soluble carbohydrate, and simultaneously decrease (p<0.05) the contents of NDF, ADF, ADL, and crude ash. Fermentation products such as lactic acid, acetic acid, and propionic acid decreased (p<0.05) due to the additions of essential oils. Meanwhile, on the microbial parameters, it was found that the use of essential oils was able to reduce the mold population on silage (p<0.01). In conclusion, the addition of essential oils as silage additives maintained nutrient quality, decreased fiber content, and inhibited fungal growth.