Development of Na+ transport in the chicken colon

Area of Science:

• Physiology
• Developmental Biology
• Gastroenterology

Background:

• Colonic sodium (Na+) transport is vital for fluid balance.
• Developmental changes in intestinal ion transport are critical for adaptation after birth.
• Understanding these changes is key to pediatric and comparative physiology.

Purpose of the Study:

• To investigate developmental changes in chicken colon Na+ transport.
• To assess the impact of salt intake on Na+ absorption and Na+, K+-ATPase activity.
• To explore the role of amiloride sensitivity in developmental Na+ transport.

Main Methods:

• Measured amiloride-sensitive short-circuit current (a marker for electrogenic Na+ transport) in chicken embryos and chicks.
• Assessed Na+, K+-ATPase activity in colon tissue.
• Varied dietary salt intake (low-salt vs. high-salt 0.9% NaCl).

Main Results:

• Amiloride-sensitive Na+ transport was absent in embryos but increased post-hatching, particularly on a low-salt diet.
• High salt intake (0.9% NaCl) completely prevented the development of amiloride-sensitive Na+ transport.
• Na+, K+-ATPase activity increased with development but was unaffected by salt intake.
• Amiloride-sensitive Na+ transport showed a gradual increase for at least 15 days post-hatching.

Conclusions:

• Chicken colonic Na+ transport undergoes significant developmental changes.
• Low-salt diet promotes the maturation of electrogenic Na+ absorption in the colon.
• These adaptations are crucial for maintaining sodium balance during early life, with potential aldosterone involvement.