Involvement of 4-pentenoic acid in causing quality deterioration of nettle silage: study of antibacterial mechanism

Nettle has attracted the attention of scientists due to its several benefits for animals as non-conventional feed sources. However, as for challenge, nettle is difficult to ensile (poor quality), which is an obstacle for nettle use. In the present manuscript, we investigated the effect of <i>Pediococcus</i> on the characteristics of nettle silage and clarified the mechanisms of 4-pentenoic acid against <i>Pediococcus</i>. Our findings suggested that <i>P. pentosaceus</i> could improve nettle silage quality at a significant level through decreased production of ammonia (decline percentage was 21.41%-31.73%) during ensiling, while it could not well improve the quality of nettle silage due to the interference effect of 4-pentenoic acid as an antibacterial substance. The mechanism of 4-pentenoic acid against <i>P. pentosaceus</i> was mainly through inhibition of fatty acid synthesis (fabG) and expression of acid tolerance protein (accA), resulting in destruction of the cell wall in <i>P. pentosaceus.</i> Our finding could give a new clue for better use of nettle silage.