Aims

In order to study the adaptation of the respiratory organ and the O2 metabolism due to training, we subjected adult zebrafish (Danio rerio) to endurance exercise for 5 weeks. After the training period, the swimmer group showed significant increase in swimming performance, body weight and length.
The gills increased their volume significantly (p<0.05) by 11.8 % from 0.490 mm3 to 0.549 mm3. The space-filling complexity of the gills dropped significantly (p<0.01) by 8.2 % from 38.8 % to 35.9 %. We conclude that the respiratory organ of the adult zebrafish shows a high plasticity.