Investigation of Different Nutritional Effects of Dietary Chromium in Fish: A Literature Review.

The supply of food for the world population that is increasing is one of the concerns of governments. The Food and Agriculture Organization of the United Nations assessment shows that the aquaculture industry could help meet food needs for human communities. The aquaculture industry also relies on providing a feed of high quality. Minerals are one essential component of an aquatic diet. Chromium (Cr) is a trace element that finds the form of Cr+3 (trivalent) and Cr+6 (hexavalent) in nature and food items. Studies show that exposure to Cr waterborne have toxicity effects on fish. However, oral exposure to Cr has a different impact on fish. Cr is usually involved in the metabolism of fats, carbohydrates, proteins, growth function, enzyme functions, etc. This element could play a significant role in fish nutrition and physiology. Cr as a dietary supplement can improve growth performance and adjust the metabolism of carbohydrates and lipids. However, high concentrations of Cr can be toxic to fish. Although the physiological effects of Cr on aquatic organisms are well known, there are still ambiguities in determining the appropriate concentration in the diet of some species. Maybe, the physiological response of fish depends on the concentration, origin, and chemical composition of Cr, as well as the biological and individual characteristics of the fish. Therefore, it is necessary to estimate the appropriate concentration of Cr in fish diets. This article aims to summarize the available information about the effect of Cr on various physiological indicators and fish growth. Therefore, this information may help to find the appropriate concentration of Cr in the diet.