Zebrafish embryos derived in GF conditions were either transitioned to conventional microbiota (CNV) at 3 days post fertilization (dpf) or maintained GF. Total RNA isolated from zebrafish larvae at 6 dpf was analyzed for hmox1 expression by real-time RT-PCR. (A) Zebrafish embryos were injected with nrf2 morpholino (MO) to knockdown nrf2 mRNA translation, or standard control MO, then derived into GF conditions. At 3 dpf, zebrafish were transitioned to conventional microbiota or maintained GF. At 6 dpf, hmox1 expression was again analyzed by real-time RT-PCR. (B) Results of gstp1 expression in nrf2 MO and control MO treated zebrafish are shown as a positive control. Data represent mean ± SEM of biological duplicate pools (5–10 larvae/pool, 2 pools/condition) normalized to rpl32 mRNA levels.