Fermentation quality, aerobic stability and in vitro gas production kinetics and digestibility in total mixed ration silage treated with lactic acid bacteria inoculants and antimicrobial additives

Abstract

The objective was to evaluate the effectiveness of lactic acid bacteria (LAB) inoculants and chemical additives on the fermentation quality, aerobic stability and in vitro gas production kinetics and digestibility of total mixed ration (TMR) silage. Total mixed ration (568 g/kg dry matter (DM)) was ensiled with six experimental treatments: (1) no additives (control); (2) Lactobacillus buchneri (LB; applied at 1 × 106 cfu/g fresh weight (FW)); (3) Lactobacillus casei (LC; applied at 1 × 106 cfu/g FW); (4) calcium propionate (CAP; applied at 0.5% FW); (5) sodium diacetate (SD; applied at 0.5% FW); (6) potassium sorbate (PS; applied at 0.1% FW). All silos (18 L) were opened for fermentation quality, in vitro gas production kinetics and digestibility analysis after 90 days of ensiling, and then subjected to aerobic stability test for 14 days. All the TMR silage was well-preserved with low pH (4.36 ∼ 4.66) and acceptable levels of butyric acid (1.02 ∼ 2.51 g/kg DM) and ammonia nitrogen (86.3 ∼ 107 g/kg total nitrogen). All the groups were steady during 14 days of aerobic exposure, while SD group was more stable with lower (p < 0.05) yeast (4.60 vs. 5.17 ∼ 5.77 log10 cfu/g FW) and mould (3.33 vs. 4.12 ∼ 4.64 log10 cfu/g FW) populations than other treated groups on day 14. Moreover, SD group had the highest (p < 0.05) in vitro digestibility of dry matter (67.8 vs. 56.6 ∼ 63.5%) and neutral detergent fibre (61.7 vs. 50.5 ∼ 57.4%) among all groups. Overall, SD is recommended as additive to improve fermentation quality, in vitro ruminal digestibility, and aerobic stability of TMR silage.HIGHLIGHTS After 14 days of aerobic exposure, the yeast and mould populations in TMR silage can be efficiently inhibited by sodium diacetate treatment. Sodium diacetate treatment evidently enhanced in vitro digestibility of dry matter and neutral detergent fibre compared to other treatments. Sodium diacetate is recommended as additive to improve fermentation quality, in vitro ruminal digestibility, and aerobic stability of TMR silage.

Keywords

• aerobic stability
• chemical additives
• fermentation quality
• lactic acid bacteria inoculants
• total mixed ration silage