Magnesium Transport in Fish Intestine

Abstract

ABSTRACT Literature on the mechanisms of magnesium transport through fish intestine is scarce. Indirect evidence for a net magnesium transport via the intestinal tract of fish has been established by dietary experiments (e.g. with carp Cyprinus carpio L. and nile perch Oreochromis niloticus Peters), showing that dietary magnesium is essential for the growth of these fish (Ogino and Chiou, 1976; Dabrowska et al. 1989). Nakamura and Hirano (1986) suggested ‘solvent drag’ as a mechanism for net magnesium transport in eel Anguilla japonica intestine. For mammals, the reports on this topic are equivocal. In the small intestine of the rat, diffusion (Ross, 1962; Aldor and Moore, 1970; O’Donnell and Smith, 1973) as well as solvent drag (Behar, 1974) were reported to underlie magnesium absorption, although the possibility of an active transport component was kept open by these authors. For the intestine of guinea pig, active transport of magnesium was demonstrated (Ross and Care, 1962; Partridge et al. 1987). This communication deals with magnesium transport across stripped intestinal epithelium of freshwater tilapia and its possible mechanisms.