Effects of hexanoic acid, Lactobacillus plantarum and their combination on the fermentation characteristics of Napier grass

Abstract The study aimed to investigate the effects of hexanoic acid (Hex), Lactobacillus plantarum (Lp) and their combination on the fermentation profile of Napier grass ( Pennisetum purpureum ) silage. Napier grass was ensiled without additive (C), Lp, Hex and combinations of Hex + Lp for 60 d. Silage inoculated with Lp exhibited rapid accumulation of lactic acid (LA) and decline of pH over the ensiling as compared to the C silage. The accumulation of LA, acetic acid (AA) and the decline of pH and water soluble carbohydrates (WSC) in silages with Hex and Hex + Lp were slower than those of silage without Hex over the ensiling. The addition of Hex, Lp and Hex + Lp ( P 0.01) depressed the accumulation of ammonia nitrogen (AN) and ethanol concentrations over the ensiling as compared to the C silage. Additive with Hex inhibited the activity of lactic acid bacteria (LAB) and yeasts ( P 0.01) as compared to those without Hex. The addition of Lp improved fermentation quality of Napier grass silage, while Hex and Hex + Lp caused an intermediate fermentation with greater antimycotic effects and WSC preservation. This study showed that Hex alone or in combination with L. plantarum were potential fermentation inhibitors with antimycotic effects that could persist throughout the ensiling.