The effects of dietary NaCl supplement on hypo-osmoregulatory ability and sea water performance of Arctic charr (Salvelinus alpinus L.) smolts |
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Authors: | Magne Staurnes,& Bengt Finstad |
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Affiliation: | Department of Zoology, Norwegian University of Science and Technology (NTNU), N-7034 Trondheim, Norway;Norwegian Institute for Nature Research, Tungasletta 2, N-7485 Trondheim, Norway |
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Abstract: | Groups of one‐year‐old smolts of Arctic charr (Salvelinus alpinus L.) reared under a simulated natural photoperiod were fed pelleted feed with a NaCl content of either 1.5% or 9.5% for 6 weeks before release in a river in northern Norway. There were no differences in growth before release between fish fed the two diets. Smolts fed the 9.5% NaCl diet had better hypo‐osmoregulatory ability than those fed the 1.5% diet, and a level of gill Na+‐K+‐ATPase activity that was several times higher. One of the two groups that had been fed the 9.5% NaCl diet had both a significantly higher recapture rate and growth in sea than the two groups fed the 1.5% NaCl diet, whereas this was not true for the other 9.5% NaCl diet group. The results indicate that a NaCl‐enriched diet could be used to ensure sufficient hypo‐osmoregulatory ability of charr smolts that would otherwise have insufficient regulatory ability. |
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