Mineral requirements of fish: a systematic review

Abstract

Meta-analysis of literature data on mineral and trace element requirements of fishwas performed with the major objectives of identifying appropriate response cri-teria and the factors affecting the minimal dietary inclusion levels. The primarydata set included 25 studies on available P, 20 on Ca, 24 on Mg, 5 on K, 37 forZn, 23 for Se, 19 for Mn, 16 for Fe and 13 for Cu. Broken line regression analysiswith linear plateau model (P, Ca, Mg and K) or two-linear line model (Zn, Cu,Fe, Mn and Se) was used for determining the minimal dietary inclusion levels.Vertebral mineral concentration (P, Ca, Zn and Mn), whole-body mineral levels(Mg, K and Fe) and hepatic enzyme activity (Se) were found to be the mostappropriate criteria for the respective minerals analysed. In general, weight gainas the criterion resulted in a lower estimate (by 18–42%) than those obtainedusing whole-body or vertebral mineral concentrations as response criteria. Theanalysis also showed that different fish species do not show large variations in themineral and trace element concentrations in the whole body and tissues. Factorssuch as species group and digestive physiology, type of experimental diet usedand dietary interactions, type of mineral source and mineral concentration ofwater were found to affect the minimal dietary inclusion levels of certain minerals.Besides the meta-analysis, research needs in mineral nutrition of fish with refer-ence to growing changes in dietary strategies and rearing systems are discussed.