Iron acquisition by teleost fish.

Area of Science:

• * Aquatic physiology and molecular biology
• * Nutritional biochemistry in fish

Background:

• * Iron is essential for teleost fish, crucial for cellular respiration and oxygen transport.
• * Excess iron poses toxicity risks, necessitating precise uptake regulation.
• * Understanding iron acquisition mechanisms is vital for fish health and aquaculture.

Purpose of the Study:

• * To review current physiological and molecular knowledge of iron acquisition in teleost fish.
• * To examine iron uptake mechanisms in freshwater (gills) and marine (intestine) teleosts.
• * To summarize geochemical factors influencing aquatic iron bioavailability.

Main Methods:

• * Literature review of physiological and molecular studies on fish iron metabolism.
• * Analysis of geochemical processes affecting iron in aquatic environments.
• * Identification of conserved iron transport proteins in teleost fish.

Main Results:

• * Iron uptake occurs preferentially across the apical membrane in the ferrous (Fe2+) state in both gills and intestines.
• * Homologues of the Slc 11a family of Fe2+ transporters are present in teleost fish.
• * Iron uptake is likely facilitated by reductases converting ferric (Fe3+) or organic iron to Fe2+.

Conclusions:

• * Teleost fish possess specific molecular mechanisms for iron acquisition, primarily involving Fe2+ transport.
• * The Slc 11a family and associated reductases play a key role in fish iron uptake.
• * Balancing iron uptake is critical for preventing deficiency and toxicity in teleost fish.