Dietary supplementation with Cuscuta chinensis improves ovarian function and production performance in aged laying hens via modulation of steroid hormone biosynthesis and gut microbiota.

Declining reproductive performance due to ovarian aging is a critical challenge in layer farming. This study investigated the mechanism by which Cuscuta chinensis (TSZ), a herb with known estrogen-like activity, improves ovarian function in aged laying hens. Network pharmacology analysis identified ten candidate anti-ovarian aging compounds in TSZ, with IL-1B, IL-6, and EGF predicted as core targets. Subsequently, an 8-week feeding trial was conducted using 432 healthy 46-week-old Jing Brown 1 laying hens, which were randomly assigned to four groups and were fed a basal diet supplemented with 0%, 0.5%, 1%, or 2% TSZ. An integrated multi-omics approach-combining serum metabolomics, ovarian transcriptomics, and cecal 16S rRNA sequencing-was employed to systematically map the responsive pathways. Dietary TSZ significantly reduced the rate of abnormal eggs and increased Haugh unit values (P < 0.05), with the 0.5% supplementation group showing optimal overall production performance. TSZ significantly increased serum levels of estradiol and follicle-stimulating hormone (P < 0.05), up-regulated ovarian estrogen receptor gene expression, and down-regulated pro-inflammatory cytokine genes in the ovary (P < 0.05). Integrated omics analysis revealed activation of the ovarian steroid hormone biosynthesis pathway. Furthermore, TSZ reshaped the cecal microbiota structure, notably enriching butyrate-producing bacteria such as Butyricicoccus pullicaecorum and Butyricimonas, whose abundances correlated positively with multiple steroid hormone-related metabolites. Collectively, these results demonstrated that TSZ improved ovarian function in aging hens by modulating estrogen signaling, suppressing local ovarian inflammation, and promoting steroidogenesis-effects that were closely linked to TSZ-mediated restructuring of the gut microbiota and regulation of the gut-ovary axis. This work provides a mechanistic foundation for developing TSZ as a natural feed additive to mitigate reproductive aging in laying hens.