Extended one-generation reproductive toxicity study evaluating gardenia blue in Sprague Dawley rats

Gardenia blue powder was administered at 0.5%, 2.5%, or 5.0% in feed to male and female Sprague Dawley rats in an Extended One-Generation Reproductive Toxicity Study (OECD Test Guideline 443). The dosed diet began 14 days before mating and was continued at the same concentration level for the entire study for all parental animals (P₀) and offspring (F₁). At weaning, offspring were allocated into one of 5 cohorts for different endpoints. P₀ and F₁ animals had blue urine, blue or black feces, and blue discolorations in gastrointestinal organs, mesenteric lymph nodes, and kidneys. This treatment-related finding was not considered adverse as there were no histopathologic correlates. There was a dose-related increase in sperm concentration in P₀ and F₁ males. There were dose-related increases in heart weights of F₁ postnatal day (PND) 21 males, male and female thyroid weights, and female TSH levels of PND 91 F₁ offspring, with no histopathological correlate. There were no consistent treatment-related adverse effects on any other parameters evaluated for general toxicity, reproductive toxicity, developmental neurotoxicity, or developmental immunotoxicity. The highest dietary concentration (5.0%) of gardenia blue powder was the no observed adverse effect level (NOAEL) for male and female rats at all life stages evaluated.