Chronic dietary exposure to the food preservative tert-Butylhydroquinone (tBHQ) impairs zebrafish (Danio rerio) survival, growth, organ development, and gene expression in Nrf2a-dependent and independent ways

Tert-Butylhydroquinone (tBHQ), a preservative used to prevent oxidative deterioration of oil, fat, and meat products, has been linked to both chemoprotective and adverse effects. This study investigates the impact of chronic dietary tBHQ on survival, growth parameters, organ development, and gene expression in zebrafish (Danio rerio). As tBHQ activates the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2a), a zebrafish line with a mutation in the DNA-binding domain was used to identify Nrf2a-dependent vs. independent effects. Homozygous Nrf2a wildtype (wt) and mutant (m) larvae were fed a diet containing 5% tBHQ or a control diet. Survival and growth parameters were assessed at 15 days and at 5 months, and samples collected for RNA sequencing at 5 months. Chronic dietary exposure to tBHQ throughout the larval and juvenile periods negatively impacted growth and survival. RNA-seq analysis found differentially expressed genes related to growth and development and upregulation of several immune pathways. The findings herein demonstrate that chronic dietary tBHQ exposure may impair growth and survival in both Nrf2a dependent and independent manners. Comparative gene expression profiling analysis of RNA-seq data for whole zebrafish (Danio reio) fed a 5% Tert-Butylhydroquinone (tBHQ) or control diets for 5 months in homozygous Nrf2a wildtype (wt) and mutant (m) zebrafish