Effect of adding sorbic acid on the fermentation quality of Italian ryegrass silage

The experiment was carried out to investigate the influence of adding sorbic acid on the fermentation quality and water soluble carbohydrate (WSC) content of Italian ryegrass (Lolium multiflorum Lam) silage, and to determine the proper application rate of sorbic acid. The treatments were designed as follows: control (0), 0.05%, 0.10%, 0.15% and 0.20% of sorbic acid addition (fresh weight basis of Italian ryegrass). The results showed that decrease the pH value and the contents of ammonia nitrogen/total nitrogen (AN/TN) and butyric acid were significantly (P0.05) decreased, and the contents of WSC and dry matter were significantly (P0.05) increased after 30 days fermentation compared with control. However, there were not significantly (P0.05) difference in lactic acid/acetic acid and contents of the lactic acid, acetic acid and total volatile fatty acid (VFAs). It could suggest that 0.10% of sorbic acid was the proper application rate.