Essential oil and apple pomace affect fermentation and aerobic stability of alfalfa silage

Abstract

This study assessed the effects of the additions of an essential oil (EO), composed of ricinoleic acid, cardol, cardanol, and apple pomace, on fermentation quality and aerobic stability of alfalfa silages. The experimental treatments consisted of T1) alfalfa (control), T2) alfalfa with EO, T3) alfalfa (75%) with apple pomace (25%), T4) alfalfa (75%) with apple pomace (25%) and EO, T5) alfalfa (50%) with apple pomace (50%), T6) alfalfa (50%) with apple pomace (50%) and EO, T7) alfalfa (25%) with apple pomace (75%), and T8) alfalfa (25%) with apple pomace (75%) and EO. The addition of apple pomace decreased the silage pH compared with the control (P <0.01). Apple pomace at 25% level increased the total volatile fatty acid ( iVFA) content (P <0.05). Essential oil (EO) decreased tVFA and increased dry matter (DM) content 90 days after ensiling (P <0.01). Apple pomace decreased ammonia (N-NH3), crude protein (CP), and crude ash (CA) content and increased the amounts of neutral detergent fibre (NDF) and acid detergent fibre (ADF) (P <0.01). Essential oil and apple pomace (level 75%) increased effective digestibility (P <0.05). Apple pomace decreased aerobic stability and the addition of EO increased aerobic stability (P <0.05). Thus, use of apple pomace as a source of fermentable carbohydrate and/or the addition of EO in the preparation of high-quality alfalfa silage is recommended to offset its high buffering capacity and low carbohydrate content.