A Combination of Novel Microecological Agents and Molasses Role in Digestibility and Fermentation of Rice Straw by Facilitating the Ruminal Microbial Colonization

In this study, we evaluated the effect of microecological agents (MA) combined with molasses (M) on the biodegradation of rice straw in the rumen. Rice straw was pretreated in laboratory polyethylene 25 × 35 cm sterile bags with no additive control (Con), MA, and MA + M for 7, 15, 30, and 45 days, and then the efficacy of MA + M pretreatment was evaluated both in vitro and in vivo. The scanning electron microscopy, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy results showed that the MA or MA + M pretreatment altered the physical and chemical structure of rice straw. Meanwhile, the ruminal microbial attachment on the surface of rice straw was significantly increased after MA+M pretreatment. Furthermore, MA + M not only promoted rice straw fermentation in vitro but also improved digestibility by specifically inducing rumen colonization of Prevotellaceae_UCG-001, Butyrivibrio, and Succinimonas. Altogether, we concluded that microecological agents and molasses could be the best choices as a biological pretreatment for rice straw to enhance its nutritive value as a ruminant's feed.