Short CommunicationDietary Zn and the subsequent organotropism in fish: No influence of food quality, frequency of feeding and environmental conditions (pH and temperature)

- Distribution and concentration of dietary Zn was experimentally assessed in turbot.
- Zn organotropism is not affected by food or pH and temperature.
- Consistency in the Zn organotropism can be explained by its homeostasis in fish.

Trophic transfer of Zn in fish is affected by the type of food and environmental variables such as temperature. However, there is still a lack of knowledge regarding the effects of such factors on Zn organotropism. For this reason, a series of experimental studies have investigated how the distribution and the concentration of Zn is affected by some environmentally-relevant factors (food quality, food availability, water pH, and temperature) in turbot Scophthalmus maximus using radiotracer techniques. In three different experiments, Zn distribution in seven body compartments of juvenile turbot and the calculation of Zn concentration index (IC) for each compartment were compared. Its distribution as well as its concentration in the body compartments of juvenile turbots were not affected by the experimental conditions tested. This apparent consistency in the Zn organotropism can be explained by the ability of the fish to maintain Zn homeostasis at non-toxic Zn concentrations in their diet. These results are important to better understand the trophic transfer of Zn in fish under realistic environmental conditions.

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