ABSTRACT: Substituting bisphenol A with analogues is a strategy to mitigate environmental harm. Mimicking water contaminations and using zebrafish larvae, we assessed the physiological and molecular effects of bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF), comparing them to BPA. We first calculated the lethal doses (LD₅₀) using an OECD-compliant protocol, yielding the ranking: BPAF > BPF > BPA > BPS. From this broad range assessment, we examined the effects of bisphenol concentrations below each LD₅₀. We report no morphological or muscle alterations or hatching delays at 5dpf. We found altered motor-behavioral patterns at specific concentrations (100 ng/L BPS; 10 ng/L, 1000 ng/L, 10µg/L BPF; 100 ng/L, 100µg/L, 1000µg/L BPAF). For each bisphenol, we then focused on the lowest levels provoking motor changes and asked whether cardiac or brain electrophysiological adaptations underpin the phenotype. Using in vivo optical mapping, we observed an increase in high-frequency, low-amplitude brain activity, and, in the specific cases of BPF and BPAF, bradycardia. Within these particular exposure settings, transcriptomic analyses revealed shared modifications in sterol biosynthesis and immune pathways, potentially associated with the physiological effects. Low environmental concentrations of BPF, BPAF, and BPS induce adaptive responses in zebrafish larvae, with ecotoxicological implications.
