The effects of chronic developmental hypoxia on swimming performance in zebrafish

Relative to normoxia-reared fish, hypoxia-reared zebrafish Danio rerio achieved 24·9 and 21·4% slower maximal swim velocities in both normoxic and hypoxic waters, respectively. Hypoxia-reared fish also produced 26·1 and 63·9% less lactate during resting conditions across both normoxic and hypoxic waters, respectively. During exercise, this trend continued as hypoxia-reared fish produced 68·2 and 55·1% less lactate across both normoxic and hypoxic waters, respectively. This reduction in performance, rather than representing a purely pathological (maladaptive) response to hypoxia, appears to represent a fundamental shift in the metabolic response to hypoxia.