Effect of PICB on nutritional quality and bacterial community of High moisture ear corn with different moisture contents

High moisture era corn (HMEC) has become increasingly popular in dairy cow rations. However, the high moisture content of HMEC lead to protein hydrolysis during fermentation. This study aimed to find the effects of Polyphenols from involucres of Castanea mollissima Blume (PICB) on the nutritional quality, fermentation characteristic and microbial communities of HMEC with different moisture contents. Different level of PICB (CON, inoculated with LAB only; PICB1, LAB + 0.1% PICB; PICB2, LAB + 0.15% PICB; PICB3, LAB + 0.2% PICB) were added to chopped maize with cobs at different moisture contents (LM, 40% moisture contents; HM, 45% moisture contents) and silaged for 60 days. The results showed that crude protein (CP), dry matter (DM), neutral detergent fibres (NDF) contents in LM were highly significantly higher than in HM (p<0.01). Among the groups, PICB3 had the highest CP and DM contents, the lowest NDF contents. Lactic acid, the ratio of lactic acid/acetic acid (LA/AA) were significantly higher in LM than in HM, while pH, AA and ammonia nitrogen were highly significantly lower than in HM (p<0.01). Among the groups, PICB3 had the highest LA contents, the lowest NH3-N contents. The alpha diversity of the HMEC bacterial community with PICB was insignificant compared to CON. Spearman's correlation analysis showed that Lactobacillus were positively correlated with LA content. Weissella, Pantoea, Klebsiella and Serratia were positively correlated with ammonia nitrogen content. In conclusion, 0.2% PICB can be used as an additive to preserve nutrients and improve fermentation quality in HMEC.