Optimum dietary calcium requirement of Hypophthalmichthys molitrix juveniles

Abstract

Calcium (Ca) is one of the essential minerals in both terrestrial and aquatic animals (NRC, 2011). It plays key roles in osmoregulation, blood clotting, acid-base equilibrium, bone mineralization, nerve transmission, contraction of muscles, the integrity of cell membrane, skeletal development and enzyme activation (NRC, 2011). Bones and scales are considered the major sites for Ca deposition in fish . In teleost, about 99% Ca is incorporated into their scales and bones (Hossain & Yoshimatsu, 2014). Deficiency of Ca resulted in stunted growth, skeletal deformities and low mineralization in fish (Liu et al., 2021).Generally, it is accepted that most of the fish have the ability to meet their Ca requirement by drinking surrounding water (Lall, 2002).Different structures of fish such as oral epithelia, gills and fins are involved in absorption; however, gills are regarded as the most effective organs for Ca absorption (Flik & Perry, 1989). Freshwater fish have more ability to uptake Ca from surrounding water than marine fish as they have higher serum Ca level than freshwater (Hossain & Yoshimatsu, 2014). They can meet their Ca requirement either