Nutritional physiology of Zn and its relationship with lipid metabolism for aquatic animals: a review

Zinc (Zn) is an essential trace element, and maintains the normal growth, development and nutrient metabolism of aquatic animals. To decipher the mechanism of Zn regulating nutrient metabolism in aquatic animals, the present paper summarizes the research progress involved in dietary Zn requirements and the key factors influencing Zn requirements, structures and functions of key genes and proteins (such as ZnTs and ZIPs families, MTs and MTF-1) relevant with Zn homeostatic regulation, and the effects and mechanism of Zn influencing lipid deposition and metabolism. At present, although some progresses have been made in the Zn nutrition, physiology and metabolism of aquatic animals, many underlying problems remain unsolved and further investigations are needed: ① wide-accepted evaluating standards for the optimal dietary Zn requirement; ② the structure and function of key genes and proteins in the regulation of Zn homeostasis, and the revelant mechanism of absorption, transport and homeostasis of Zn in aquatic animals, which provides the basis for the addition of dietary Zn sources; ③ the signal pathways and molecular mechanism of Zn regulating nutrient metabolism, which provides the reference for the precise regulation of zinc nutrition in aquatic animals.