Nutritional applications of species of Spirulina and Chlorella in farmed fish: A review

Microalgae contain 50% crude protein value, which is comparable with the amino acid profile of fish meal, and high levels of polyunsaturated fatty acids make their use in animal feeding and nutrition extremely effective. Owing to the high price of fish meal and fish oil, cheaper suitable alternatives are being sought, and species of Spirulina and Chlorella could be a major plant protein source in farmed fish nutrition. Many studies have assessed the suitability of these microalgae in the diet of various fish species. This review highlights the influence of Spirulina on the growth enhancement of different fish species. Numerous beneficial effects of microalgae supplementation have been reported, including growth promotion in carp (Labeo rohita) and tilapia (Oreochromis niloticus), stimulation of immunity in rainbow trout (Oncorhynchus mykiss) and enhancement of reproductive performance in yellowtail cichlid (Pseudotropheus acei). Novel investigations have concluded that Spirulina could be utilized in the treatment of wastewater containing outflow from fish culture activities because of its effectiveness in eliminating heavy metals and metabolising excess feed present in water outflow. The aquaculture industry could integrate the treatment of water outflow with production of Spirulina as an additive to fish diets.