A Review on the Function of Carotenoid Supplements in Improving Skin Pigmentation and Growth of Ornamental Aquatic Animals

Carotenoids are a group of natural fat-soluble pigments that are mainly produced from natural sources such as plants and animals, however, carotenoids are also synthetically produced and used in various sectors of the aquaculture industry. The present study was conducted with the aim of investigating the function of carotenoid supplements in improving skin pigmentation and growth of aquatic animals, especially fish. One of the most important functions of carotenoids is their pseudo-antioxidant function against free radicals and oxidizing agents, increasing the body's immunity against bacterial and fungal diseases. In addition, they play a vital role in improving the growth, survival and reproduction of aquatic animals, as well as, interfering with the infant stages or the early stages of feeding. So far, various researches have been reported about the addition of carotenoid supplements to the diet of aquatic animals, which have had positive and significant effects on improving skin color and also increasing the growth of many aquatic species. Among these aquatic species are Atlantic salmon (Salmo salar), Red tilapia (Oreochromis niloticus), Hyphessobrycon callistus, koi carp (Caprinus carpio L.), goldfish (Carassius auratus), rainbow trout (Oncorhynchus mykiss), Larimichthys crocea, green swordtail (Xiphophorus hellerii), bighead catfish (Clarias macrocephalus) and channel catfish (Ictalurus punctatus). The results showed that regarding the adverse effects of artificial carotenoids on the growth of aquatic animals, it is necessary to use plant sources in aquatic food in order to improve the color of the skin and also to increase the growth and survival rate of aquatic animals in aquarium environments. The present study focuses on the extraction of carotenoids from plant sources, including various microalgae such as Haematococcus pluvialis, Chlorella vulgaris, Dunaliella salina, and Arthrospira maxima in the implementation of this matte. The implementation of these activities can help to further promote the ornamental aquatic industry at the international level and also to create sustainable employment in Iran.