Selenium yeast improves egg production performance by increasing antioxidant capacity, reproductive hormone levels and yolk precursor synthesis in late peak laying hens

, LH and Prog (P < 0.05), along with upregulated expression of FSHR, and LHR in the ovary as well as Erα and Erβ in the liver (P < 0.05). SY supplementation also significantly enhanced the expression of genes involved in yolk precursor synthesis, including APOVLDLⅡ, VTGⅡ and Apo B (P < 0.05). Finally, hens receiving 0.30 mg/kg SY showed significantly higher levels of VTG, VLDLy and VLDLR in the liver, serum and ovary (P < 0.05). However, SY had no significant effects on cecal microbial diversity or dominant bacterial taxa (P > 0.05). In summary, dietary SY supplementation can improve laying performance in hens by enhancing reproductive hormone levels, boosting antioxidant capacity in hepatic and ovarian tissues and promoting yolk precursor synthesis.