Dietary Zinc Oxide for Growth and Immune Stimulation of Aquatic Animals Species: A Review

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Fish use zinc for various vital physiological processes throughout their life cycle. It is necessary for the typical development, growth, and upkeep of fish. Many metalloenzymes and their involvement as a cofactor in several enzyme systems are the foundations of the major functions of zinc. Fish can absorb zinc from both the water environment and dietary sources. As zinc is involved in many processes of cellular metabolism, adding zinc to the diet increases the growth rate of fish. Nano-zinc oxide (nano-ZnO) has been shown to promote fish growth more than other traditional inorganic zinc forms. Although exposure to nano-ZnO resulted in histological abnormalities in several different tissues and organs, changes in the small intestinal tissues may have facilitated the transit of feed to the site of absorption, increased the capacity to absorb various nutrients, and provided protection from pathogens. In general, fish hematological and blood biochemical profiles improved with dietary zinc incorporation. When fed in small amounts, zinc can also function as an antioxidant. Although dietary nano-ZnO are thought to be nontoxic and healthy for fish, there is more bioaccumulation of zinc nanoparticles than zinc bulk particles in several tissues. There is a need for more research on the use of dietary zinc as a supplement in the diets of various aquatic species since there are a few variables that could affect the levels of dietary zinc and make it more difficult to estimate its required levels. The actual bioavailability of ZnO nanoparticles to animals also needs to be determined. In this review, we have tried to evaluate and draw conclusions about the advantages of zinc in various forms and its potential application as a mineral supplement to various aquatic animals species.