Exercise improves growth, alters physiological performance and gene expression in common carp (Cyprinus carpio)

Area of Science:

• Aquaculture and Fish Physiology
• Animal Exercise Physiology

Background:

• Aquaculture aims to enhance fish production efficiency.
• Induced swimming is a potential method to improve fish growth performance.

Purpose of the Study:

• To investigate the effects of different induced swimming regimes on the growth, metabolic efficiency, and physiological capacity of common carp (Cyprinus carpio).

Main Methods:

• Common carp were subjected to three exercise regimes (0.0, 1.5, and 2.5 body lengths per second) for four weeks.
• Growth parameters, feed conversion efficiency, hepatosomatic index, tissue energy stores, plasma ion levels, gene expression (IGF-I axis, growth hormone receptors, stress response genes), oxygen consumption, and critical swimming speed (Ucrit) were measured.
• Ammonia excretion and plasma ammonia levels were also assessed.

Main Results:

• Fish exercised at 2.5 BL/s exhibited significantly increased weight gain, specific growth rate, feed conversion efficiency, and hepatosomatic index compared to controls.
• While tissue energy stores and plasma ion levels remained stable, gene expression analysis showed upregulation of IGF-I and growth hormone receptors in the liver at 2.5 BL/s.
• No significant training effect was observed in oxygen consumption or Ucrit, but prolonged swimming at 1.5 and 2.5 BL/s improved ammonia excretion.

Conclusions:

• Sustained induced swimming at 2.5 BL/s enhances growth and physiological fitness in common carp without compromising energy metabolism or ion regulation.
• Exercise can be a valuable tool for increasing fish production efficiency in commercial aquaculture.