This study investigated the effects of dietary Tribulus terrestris extract (0, 100, 1000, or 2000 mg/kg) on growth, health, and reproductive physiology in common carp (Cypri- nus carpio). Over 60 days, fish fed 100 and 1000 mg/kg exhibited higher survival rates (P < 0.05), though growth metrics (final weight, FCR, SGR) remained unchanged (P > 0.05). Reproductive indices displayed sex-specific responses: males showed elevated gonadosomatic index (GSI) at 100–1000 mg/kg, while females had increased GSI at 2000 mg/kg (P < 0.05). T. terrestris extract at 1000 mg/kg significantly reduced female GSI (P < 0.05), while no dose increased male testosterone, suggesting species- and sex-specific efficacy. Blood biochemistry revealed dose-dependent effects, including elevated triglyc- erides (males, 2000 mg/kg; females, 1000–2000 mg/kg), cholesterol peaking at 100 mg/ kg (both sexes), and reduced globulin levels (P < 0.05). Liver function markers SGOT and SGPT increased at higher doses (P < 0.05), while alkaline phosphatase (ALP) decreased at 1000–2000 mg/kg, and lactate dehydrogenase (LDH) declined in males at 1000 mg/kg. Gene expression analysis highlighted significant upregulation of ovarian NRF2 (linked to oxidative stress response), whereas GDF9 (critical for folliculogenesis) remained unaf- fected. Histologically, T. terrestris enhanced spermatogenic maturity (increased spermato- cytes/spermatozoa) and delayed ovarian development in females at 1000 mg/kg, correlating with reduced estradiol (P < 0.05). These findings underscore T. terrestris as a multifunc- tional supplement for modulating male reproductive performance and female sexual matu- ration in aquaculture, with implications for broodstock management.

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