Dietary genistein supplementation enhances reproductive and bone health in late-laying hens

Aging in laying hens leads to progressive declines in production performance and egg quality, primarily due to deteriorating ovarian function and bone health. Genistein, a natural isoflavone with anti-inflammatory and antioxidant properties, shows potential as a dietary intervention to alleviate age-related physiological decline. This study evaluated the effects of dietary genistein supplementation on ovarian and skeletal health in aging laying hens. A total of 180 Hy-Line Brown laying hens (60 weeks old) were randomly assigned to either a control group (CON) receiving a basal diet or a genistein group (GEN) supplemented with 20 mg/kg genistein for 15 weeks. Genistein significantly increased HDEP during 66-76 weeks of age, increased HHEP during 66-76 weeks of age, and improved eggshell quality at both 69 and 76 weeks (P < 0.05). At 76 weeks of age, ovarian histology revealed reduced inflammatory infiltration, increased follicle numbers, and decreased follicular atresia by genistein supplementation. Antioxidant enzyme activities of SOD and CAT were elevated, whereas MDA levels and pro-inflammatory cytokines (TNF-α, IL-1β) were markedly reduced in the GEN group (P < 0.05). The gene set enrichment analysis (GESA) showed enrichment of pathways related to steroid hormone biosynthesis, MAPK, and TGF-β signaling. Serum levels of LH, FSH, E2, and PROG were increased, whereas ALP and TRAP activities were decreased in the GEN group (P < 0.05). GEN enhanced bone breaking strength, bone mineral density (BMD), and bone mineral content (BMC). Furthermore, GEN upregulated the expression of estrogen receptors (ERα, ERβ), osteogenic markers (RUNX2, ALP, OCN), and the OPG/RANKL ratio (P < 0.05). Collectively, these findings demonstrate that GEN promotes ovarian and skeletal functions, thereby improving laying performance and potentially extending the productive lifespan of aging hens.