Effect of sorbic acid and dual‐purpose inoculants on the fermentation quality and aerobic stability of high dry matter rice straw silage

AimsThis study aimed to evaluate the feasibility of sorbic acid (SA) as a silage additive and its effects on fermentation quality and aerobic stability of high dry matter (DM) silage.Methods and ResultsHigh DM rice straw was ensiled with distilled water (C), 1 × 106 CFU per gram fresh weight (FW) Lactobacillus plantarum and 1 × 106 CFU per gram FW Lactobacillus buchneri (LP+LB) or SA for 45 days with a subsequent aerobic stability test. After ensiling, LP+LB silage had the highest lactic acid (LA) content and the lowest pH value, whereas SA silage had the highest DM and water‐soluble carbohydrate (WSC) contents, and the lowest ethanol and ammonia nitrogen (NH3‐N) contents among all silages (P < 0·001). Compared to C silage, SA significantly (P < 0·01) reduced the counts of yeasts but not lactic acid bacteria (LAB). During 6‐day aerobic exposure, the continuous pH increase and LA decrease were observed in C and LP+LB silages, and there was no significant change in pH, DM, NH3‐N and WSC contents of SA silage over the whole aerobic exposure. The SA addition slowed the decline of LA and acetic acid (AA) contents as well as the growth of yeasts and aerobic bacteria under aerobic exposure.ConclusionIn this study, L. buchneri could not function in high DM rice straw silage while SA effectively improved both the fermentation quality and aerobic stability.Significance and Impact of the StudyThe SA was more effective than dual‐purpose inoculants to improve the aerobic stability of high DM rice straw silage. Thus, SA can be served as a potential antifungal additive for silage with high DM.