Effects of 5,6-dimethylbenzimidazole and cobalt supplementation in high-concentrate diets on rumen fermentation and microorganisms and ruminal metabolome in sheep

Supplementing high-concentrate diets with 5,6-DMB (100 mg/d) and cobalt (0.5 mg/kg) increased ruminal pH, ammonia nitrogen concentration, and propionate concentration to a certain extent, reduced lactate concentration and lactate dehydrogenase activity, regulated ruminal microbial community structure (Quinella and Succinivibrio), and improved rumen metabolite levels (L-malate, pyruvate, and acetate concentrations). Conclusively, these findings suggest that supplementing high-concentrate diets with 5,6-DMB and cobalt may promote vitamin B12 synthesis and improve energy utilization efficiency.