Dietary Iron Regulation in Aquatic Systems

Dietary iron regulation in aquatic organisms encompasses the processes by which essential iron is acquired, transported, stored and mobilised to support vital functions such as oxygen transport, cellular respiration and immune defence. Iron is often limiting in aquatic environments due to its low solubility, driving adaptations in both waterborne uptake and intestinal absorption. Key molecular regulators, including the peptide hormone hepcidin and the iron exporter ferroportin, coordinate systemic iron balance by modulating uptake in the gut and release from storage tissues. Variation among taxa—fish, crustaceans and molluscs—reflects differences in feeding ecology, gut morphology and the use of dietary enhancers such as ascorbic acid. Environmental factors such as pH, temperature and water chemistry further influence iron speciation and bioavailability. Understanding these mechanisms has direct applications in aquaculture, where optimising dietary iron can enhance growth, disease resistance and welfare, and in conservation, where pollution or acidification may disrupt iron homeostasis in wild populations.

Research from Nature Portfolio

A foundational study in a marine medaka model revealed that larval stages finely tune dietary iron assimilation via changes in expression of iron-regulatory genes and by increasing waterborne uptake under low-iron diets. Whilst adult fish exhibited relatively stable iron acquisition regardless of supplementary levels, larvae adjusted their iron assimilation efficiency across a broad dietary range and upregulated a key iron-regulator peptide in line with dietary supply. This work underscores distinct life-stage strategies for maintaining iron sufficiency in environments where dietary sources fluctuate.

Dietary Iron Regulation in Aquatic Systems publication trend

The graph below shows the total number of articles in dietary iron regulation in aquatic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Hepcidin: A peptide hormone produced principally by the liver that inhibits iron export by inducing degradation of ferroportin.

Ferroportin: The sole known cellular iron exporter, present on enterocytes and macrophages, which releases iron into the circulatory system.

Transferrin: A glycoprotein responsible for binding and transporting ferric iron in the bloodstream and haemolymph.

Assimilation efficiency: The ratio of dietary iron absorbed and retained relative to the total ingested amount, often expressed as a percentage.

References

1. Novel insights into iron regulation and requirement in marine medaka Oryzias melastigma. Scientific Reports (2016).
2. Effects of Iron and Vitamin C on Growth Performance, Iron Utilization, Antioxidant Capacity, Nonspecific Immunity, and Disease Resistance to Aeromonas hydrophila in Chinese Mitten Crab (Eriocheir sinensis). Aquaculture Nutrition (2023).
3. Immunometabolic involvement of hepcidin genes in iron homeostasis, storage, and regulation in gilthead seabream (Sparus aurata). Frontiers in Marine Science (2022).
4. Effects of Dietary Ferroporphyrin Supplementation on Growth Performance, Antioxidant Capacity, Immune Response, and Oxygen-Carrying Capacity in Gibel Carp (Carassius auratus gibelio). Animals (2024).