Stevia rebaudiana extract (main components: chlorogenic acid and its analogues) as a new safe feed additive: evaluation of acute toxicity, sub chronic toxicity, genotoxicity, and teratogenicity.

Introduction: Stevia rebaudiana extract (SREC), primarily composed of chlorogenic acid and its analogues, is a promising feed additive with potential benefits for livestock performance, gut health, and antioxidant capacity. However, its safety evaluation has not been comprehensively studied.

Methods: The safety of SREC was assessed through a series of tests, including acute oral toxicity in mice and rats, a 90-day subchronic toxicity test in rats, genotoxicity assays (Ames test, mouse bone marrow micronucleus test, and mouse sperm abnormality test), and teratogenicity evaluation in pregnant rats.

Results: The acute oral toxicity test indicated that the LD₅₀ of SREC in mice and rats was greater than 5,000 mg/kg body weight. In the 90-day subchronic toxicity test, SREC was non-toxic at doses up to 50,000 mg/kg in feed. The Ames test showed no mutagenic effects on Salmonella typhimurium strains TA₉₇, TA₉₈, TA₁₀₀, and TA₁₀₂. No genotoxicity was observed in the mouse bone marrow micronucleus test or the sperm abnormality test, with no significant differences compared to controls (p > 0.05). Similarly, no teratogenic effects were found in pregnant rats, with normal embryonic development across treatment and control groups.

Discussion: SREC exhibited low toxicity in both acute and subchronic tests, and no evidence of genotoxicity or teratogenicity was observed. These findings suggest that SREC is safe as a potential feed additive and provide valuable reference data for its safety evaluation.