Embryonic temperature produces persistent effects on the capacity for thermal acclimation in adult zebrafish

Abstract

We examined how temperature during embryonic development (22, 27, or 32°C) influences the thermal dependence of swimming performance, muscle phenotype, and gene expression. Temperature treatments were maintained until hatching, after which fish were raised to adulthood at 27°C. Aerobic exercise performance (critical swimming speed) in adult fish was measured 1d after transfer to 22, 27, or 32°C and after 30d acclimation to 16 or 34°C. Developmental temperature had predictable effects on locomotor capacity, with 22°C embryos performing best at 22°C and worst at 32 and 34°C. Surprisingly, performance was ~20% higher in both 32°C and 22°C embryos than in 27°C embryos after 16°C acclimation. These findings were partially explained by differences in the transverse area of red (slow oxidative) and intermediate (fast oxidative) fibers in the axial swimming muscle. RNA‐Seq analysis of the white muscle uncovered large‐scale changes in the transcriptome after acclimation to 16°C. These data suggest that temperature change during a brief window in embryonic development can have a dramatic and persistent effect on thermal acclimation capacity. Supported by the EU‐FP7 project LIFECYCLE and NSERC of Canada.