IntroductionTrace minerals (TM) are essential for maintaining normal rumen microbial function; however, excessive levels may exert toxic effects on rumen microorganisms and impair fiber digestion. This study aimed to evaluate the effects of coated trace minerals (CTM) on rumen fermentation, immune function, antioxidant status, slaughter performance, and meat quality in sheep, and to identify key differential rumen bacteria, thereby elucidating mechanisms underlying trace mineral regulation of rumen homeostasis and host responses.MethodsThirty Yunnan fine-wool male sheep (4 months of age; 29.7 ± 0.3 kg) were randomly assigned to a control group (CON), an inorganic TM group (ITM), and a CTM group, with a 10-day adaptation and a 30-day feeding trial.ResultsLiver concentrations of Fe, Cu, Mn, and Zn increased in both supplemented groups compared with CON (p < 0.05), with greater accumulation observed in CTM (p < 0.05). Both ITM and CTM improved carcass characteristics, reflected in increased slaughter rate (p < 0.05) and half carcass meat rate (0.05 < p < 0.1), with CTM showing additional benefits in meat quality, including a greater reduction in shear force (p < 0.05). Immune parameters, including IgA, IgG, IgM, C3, and C4, were significantly enhanced (p < 0.05), especially in the CTM group (p < 0.05). Antioxidant capacity was also improved, with increased catalase activity and decreased malondialdehyde levels (p < 0.05). Rumen fermentation was enhanced by TM supplementation, as shown by increased microbial protein and total volatile fatty acids, including acetate, butyrate, and isovaleric acid (p < 0.05), while rumen pH tended to decrease and NH₃-N tended to increase (0.05 < p < 0.1). No significant differences were observed in alpha diversity indices among groups (p > 0.05). However, CTM selectively enriched Ruminococcus, Selenomonas 1, and Prevotella while reducing Christensenellaceae R-7 group and Bradyrhizobium abundance (p < 0.05), suggesting a microbial shift potentially favorable for fiber degradation. Correlation analysis explored potential relationships between rumen microbiota and phenotypic indicators.ConclusionIn conclusion, CTM more effectively modulate rumen microbial composition, enhance immune and antioxidant capacity, and improve carcass characteristics and meat quality compared with ITM, indicating that CTM represent a more efficient strategy for optimizing rumen function and production performance in sheep.