Effects of citric acid addition on nutritional quality and fermentation characteristics of Chamaecrista rotundifolia silage

The objective of this study was to investigate the effect of citric acid (CA) and fermentation time on the fermentation quality of Chamaecrista rotundifolia silage. Chamaecrista rotundifolia was used as the raw material and the treatments were the addition of 0 (CK), 0.1% (group Ⅰ), 0.3% (group Ⅱ), 0.5% (group Ⅲ), and 1.0% (group Ⅳ) CA to silage for 30, 45, and 60 days. After the silage process, samples were taken to measure and analyze the nutrient composition and fermentation quality of Chamaecrista rotundifolia silage. The results showed that 1) CA had little influence on the dry matter (DM) and water soluble carbohydrate (WSC) contents of Chamaecrista rotundifolia silage. 2) The crude protein (CP) and lactic acid (LA) contents of the experimental groups were significantly higher than those in CK (P < 0.05). The detergent fiber (NDF), acid detergent fiber (ADF), and propionic acid (PA) contents, pH, and the NH₃-N/TN ratio of the experimental groups were significantly lower than those for CK (P < 0.05), and the effects of groups Ⅲ and Ⅳ were better than the other experimental groups. However, the acetic acid (AA) content in group Ⅲ was significantly lower than that in the other treatment groups (P < 0.05). 3) The interaction effect between the CA additive and fermentation time had significant effects on the NDF, ADF, NH₃-N/TN, and PA contents (P < 0.05), but had no significant effects on other nutrient and fermentation indexes (P > 0.05). In conclusion, different CA levels and different fermentation times can improve the nutrient quality and fermentation characteristics of Chamaecrista rotundifolia silage and the best improvement effect was observed when the CA supplemental level was 0.5% (FM) for silage at 30 days.