Physiological effects of low-magnesium feeding in the common carp,Cyprinus carpio

✍ Scribed by van der Velden, J. A. ;Flik, G. ;Spanings, F. A. T. ;Verburg, T. G. ;Kolar, Z. I. ;Bonga, S. E. Wendelaar

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 991 KB
• Volume: 264
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402640302

✦ Synopsis

Abstract

Common carp (Cyprinus carpio) initially weighing about 100 g were fed a low‐magnesium diet for 17 weeks. The fish survived this treatment and had a healthy appearance. However, the fish became hypomagnesemic and their growth rate decreased. The bone sodium concentration increased and the magnesium concentration decreased. It thus appears that in carp, under dietary magnesium deficiency, magnesium is mobilized from internal stores and that magnesium in the bone mineral is replaced by sodium. Low‐magnesium fed carp further showed a decreased branchial Na^+^/K^+^ ‐ATPase specific as well as total activity. Unexpectedly, the opercular chloride cell density increased. We tentatively conclude that more and new chloride cells with a lower Na^+^/K^+^‐ATPase content develop during this treatment. We further conclude that adult carp require dietary magnesium for the maintenance of their magnesium balance as well as for the proper functioning of branchial ionoregulatory mechanisms. Low‐magnesium fed carp do not acclimate but appear to tolerate a dietary magnesium deficiency. © 1992 Wiley‐Liss, Inc.