Potential factors causing failure of whole plant nettle () silages.

Introduction: Nettle is kind of new feed resources and benefit for animal production. However, a few studies observed that quality of nettle silage was poor under naturally fermentation. Consider of microbial activity was the mainly factors for fermentation characteristics of silage.

Methods: Thus, the present study investigated the potential factors causing nettle silage failure through metabolome and bacterial community composition analyses during ensiling.

Results: During ensiling, the pH was >6.22, and water-soluble carbohydrate and organic acid contents stabilized after 7 d. At the genus level, , , and were the dominant bacteria (relative abundance were 30.06-39.39, 17.29-23.34, and 3.13-7.22%, respectively), with stable trends, whereas and relative abundance decreased significantly over time (relative abundance were 5.68-13.96 and 3.86-24.1%, respectively). relative abundance was <1% during the entire ensiling period, and malic acid metabolic pathway was the most important pathway. , , and were negatively correlated with malic acid, with displaying an opposite trend.

Discussion: The results suggested that activity was the lowest among lactic acid bacteria (LAB) during ensiling, which is the main reason for nettle ensiling failure, and attributable to a low capacity to compete for fermentation substrates such as malic acid against other LAB during ensiling. Additionally, anti-bacteria activity of nettle probably inhibited Enterobacter activity during ensiling. Present study probably given a solution for improve nettle silage quality through addition with malic acid.