Effect of hexanoic acid on microbial community, fermentation and hygienic quality of corn silages infested with or without toxigenic fungi

BACKROUND The study aims to reveal effects of hexanoic acid on microbial community, fermentation and hygienic quality of corn silages with or without fungal infection. Fungal infested (FI) and non-infested (NFI) whole-crop corn were separately ensiled without (control, CON) or with Hexanoic acid (Hex, 90% purity) at 0.2 g·kg-1 fresh weight (FW). RESULT The addition of Hex accelerated the pH decline during the first 5 d of ensiling regardless of fungal infestation. The lactic acid (LA) concentration in Hex silages was lower than that of CON during 45 d of ensiling, however the FI-Hex silage had the highest LA concentration among treatments on d 90. The Hex silage showed lower aflatoxin B1 (AFB1 ), zearalenone (ZEA), and deoxynivalenol (DON) concentrations than CON for FI silages. On d 5, the addition of Hex decreased the relative abundance of Klebsiella, Pantoea, and Enterobacter compared with CON regardless of fungal infestation, this inhibitory effect last until d 90 for NFI silages but disappeared for FI silages on d 90. The fungal infestation resulted in accumulation of Candida (34.05%) and Wickerhamomyces (19.46%). Hex decreased the relative abundance of Asperigillus, Issatchenkia and Penicillium for NFI silages on d 5, however its inhibitory effects was not observed in FI silages on d 5. CONCLUSION Fungal infestation was associated with poor fermentation and hygienic quality of corn silage, adding Hex accelerated the pH decline and maintained the antifungal activity until 90 d of ensiling, attenuating adverse effects of fungal infestation on the fermentation and preventing the accumulation of mycotoxins in corn silages. This article is protected by copyright. All rights reserved.