Partial replacement of corn silage with sorghum-sudangrass silage improves growth performance and rumen function in Hu sheep via microbial and metabolic modulation

The rumen hosts a diverse microbial community and serves as a natural bioreactor that efficiently utilizes plant biomass. To explore the potential of sorghum-sudangrass silage (SS) as an alternative to whole-plant corn silage (WS), this study evaluated the growth performance, rumen microbiota, serum metabolome, and rumen fermentation characteristics of Hu sheep. The aim was to assess the feasibility of SS as a feed resource and to identify specific rumen bacteria that interact with host metabolism. Feeding Hu sheep a diet containing 50% WS and 50% SS (T1 group) improved both growth performance and rumen fermentation compared to a diet of 100% WS (T0 group). In contrast, replacing WS entirely with SS (T2 group) did not affect growth performance. Microbiome analysis revealed that SS inclusion increased the relative abundance of beneficial bacteria. In particular, the T1 group showed an enrichment of Sphingomonas, while the T2 group had higher levels of Bacillus, Enterococcus, and Ruminobacter. Metabolomic analysis indicated that both T1 and T2 diets enhanced purine metabolism. Partial replacement (50%) of WS with SS improves rumen microbial composition, promotes purine metabolism, enhances rumen fermentation, and supports better growth performance in Hu sheep. These findings demonstrate that SS is a promising alternative to WS for enhancing growth and rumen function in ruminants.