The role of temperature on zebrafish ontogenic development and sensitivity to pharmaceuticals

This study assessed the effects of two emerging environmental pollutants caffeine (CAF) and metformin (METF) on juvenile zebrafish, raised at 22 °C or 27 ºC, after 96 h exposure. The temperature influenced the basal behaviour of unexposed juveniles, with higher swimming activity and a greater percentage of movements at the well edges observed in fish raised at 27 °C. A significant interaction between CAF and temperature was found for behavioural endpoints, but not for AChE activity, associated with neurotoxicity effects. CAF reduced swimming distance, increased erratic swimming, and inhibited AChE activity at 22 ºC, while at 27 ºC, CAF did not affect behaviour but increased AChE. METF exposure at 22 °C decreased swimming distance and increased erratic movements, but at 27 °C no effects were detected. Overall, temperature plays a more important role in the effects induced by CAF than METF.