Effects of Different Additives on the Quality of Rice Straw Haylage, Ruminal Fermentation Parameters and Methane Production in Hu Sheep

In this study, eight treatment groups were set up with three replicates in each group to investigate the effects of Bacillus, Lactobacillus, and molasses on the chemical composition and fermentation quality of fermented rice straw. Furthermore, an animal experiment was conducted to determine the nutrition apparent digestibility, ruminal fermentation characteristics, and methane emission in Hu sheep. The results showed that the dry matter (DM) and crude protein (CP) content in the group treated with <i>Bacillus megaterium</i> and <i>Lactobacillus acidophilus</i> (BMLB) was significantly higher than that in the group with no additive (CK) (<i>p</i> < 0.05). Compared with the CK group, all treatments with single or composite addition of Bacillus significantly reduced the content of neutral detergent fiber (NDF) and acid detergent fiber (ADF) (<i>p</i> < 0.05). The content of acetate, propionate, and NH₃-N in the BMLB group were significantly lower than those in the CK group (<i>p</i> < 0.05). In addition, the Hu sheep in the BMLB group showed a significant reduction in daily methane emission per unit of metabolic body weight. In conclusion, the BMLB treatment significantly improved the nutritional value, fermentation quality, ruminal fermentation, and methane emission of rice straw haylage in Hu sheep.