Hybrid Pennisetum (HP) is a perennial herb with a high yield and high quality, which makes it valuable for research as feed for herbivores. In order to make better use of hybrid Pennisetum as feed, this study studied the effects of cellulase (CE), Lactobacillus plantarum (LP), sucrose (SU), and their mixtures on fermentation parameters, chemical composition, and the bacterial community of hybrid Pennisetum silage. The experiment was divided into 7 treatments, silage treatment, and its abbreviation: CON (control group), CE (100 U/g FM cellulase), LP (1 × 106 cfu/g FM Lactobacillus plantarum), SU (1% FM sucrose), CE+LP (100 U/g FM cellulase + 1 × 106 cfu/g FM Lactobacillus plantarum), CE+SU (100 U/g FM cellulase + 1% FM sucrose), and LP+SU (1 × 106 cfu/g FM Lactobacillus plantarum + 1% FM sucrose). The silage bag was opened on the 60th day of ensilage for subsequent determination. The addition of CE and LP increased lactic acid content (p > 0.05). The pH and acetic acid of CE and LP were lower than CON (p < 0.05), and the crude protein content of CE was higher than CON. Cellulase and Lactobacillus plantarum can improve the quality of hybrid Pennisetum silage. Compared with Lactobacillus plantarum and sucrose, cellulase has better nutrition preservation and the ability to inhibit protein hydrolysis. 16S rRNA analysis showed that the dominant phyla were Fimicutes and Proteobacteria, and the dominant genera were Lactobacillus and Weissella. The changes in fermentation parameters and chemical components of hybrid Pennisetum silage caused by cellulase, Lactobacillus plantarum, sucrose, and their mixture may be the result of bacterial community changes.

The purpose of the experiment was to study the effects of different concentrations of Lactobacillus plantarum (LP) and Bacillus licheniformis (BL) on the quality of hybrid Pennisetum (HP) silage. The experiment consisted of five treatment groups. The control group did not use additives, and the experimental groups were added with LP or BL of 1 × 105 cfu/g fresh weight (FW) and 1 × 107 cfu/g FW, respectively. The results showed that LP and BL could increase the in vitro fermentation gas production and reduce the ammonia nitrogen (AN) content in HP silage. Water-soluble carbohydrates (WSC), lactic acid (LA) content, and gas production in the LP group were positively correlated with LP addition, and acetic acid (AA) was negatively correlated with addition. The content of WSC and LA in the LP7 group was significantly higher than that in the control group (p < 0.05), and AA was lower than that in the control group (p > 0.05). Dry matter (DM), crude protein (CP), and gas production were negatively correlated with the addition of BL, while acid detergent fiber (ADF) content was positively correlated with the addition of BL. Furthermore, in the above indicators, the BL5 group reached a significant level with the control group (p < 0.05). The results of 16sRNA showed that the use of LP and BL could increase the relative abundance of Lactobacillus and decrease the relative abundance of Weissella in HP silage compared with the control group. In conclusion, LP and BL can significantly improve the quality of HP silage. The LP7 group and the BL5 group have the best silage effect. From the perspective of gas production in in vitro fermentation, the LP7 group had stronger fermentability and higher nutritional value.

The aim of this trial was to assess whether the supplementation of vitamin E (VE) in high-concentrate diets could improve the fermentation and blood metabolism in the rumen of dairy cows, thereby modulating the degree of the subacute ruminal acidosis (SARA) response and improving the performance. Seven Holstein cows (four fitted with ruminal cannulas) were fed three diets (total mixed rations) during three successive periods (each lasted for 18 d): (1) the control diet (CON); (2) a high-grain (HG) diet, which was the control diet supplied with a 15% finely ground wheat diet (FGW); and (3) a high-VE diet (HGE), which was the control diet provided with a 15% FGW and 12,000 IU of VE/head per day. The results indicated that VE was able to alleviate the reduction in the dry matter intake (DMI) and milk fat yield in cows caused by HG diets. The supplementation of VE significantly reduced the levels of lipopolysaccharide (LPS), histamine (HIS), and the total volatile fatty acid (TVFA) in the rumen. The supplementation of VE observably increased the antioxidant capacity of the milk and plasma. In addition, VE markedly reduced the plasma levels of endotoxin, HIS, and pro-inflammatory factors. The supplementation of VE significantly enriched the differential metabolites of the purine metabolism, cysteine, methionine metabolism, and ABC transporter synthesis pathway in the serum. The supplementation of VE also significantly increased the relative abundance of Succiniclasticum and decreased the relative abundance of Treponema, thus reducing the production of TVFA in the rumen. In conclusion, considering that the cows in this trial had high ketone levels (BHBA > 2.3 mmol/L), we found that VE could improve the rumen fermentation and blood metabolism by modulating the relative abundance of rumen microorganisms, thereby mitigating a range of adverse effects caused by SARA.