Composition and nutritional efficacy of adult fairy shrimp Streptocephalus dichotomus as live feed

Success in aquaculture is based on various criteria, in which selection of a suitable feed and its potential use is important. The suitability and potential use of the adult fairy shrimp, Streptocephalus dichotomus, as a live feed was investigated. S. dichotomus contains 55% protein, 9% carbohydrate, 19% lipids, 10% ash and an energy value of 20 kJ/g, which is equivalent to Artemia sps. The amino acid composition of adult S. dichotomus was determined; the levels of essential amino acids in proteins were 7.7% lysine, 2.8% methionine, 1.6% histidine, 7.4% arginine, 4.6% isoleucine, 8.2% leucine, 4.9% valine, 4.3% glycine, and 5% threonine which are higher than those of the Artemia. Analysis of the carotenoids showed the presence of astaxanthin, canthaxanthin and β-carotene. Effective utilization of adult fairy shrimp was studied using the ornamental fish, Carassius auratus, which showed equivalent growth performance similar to Artemia. The biochemical analyses of whole tissue of the fish fed with live feeds showed their efficient utilization. Fatty acid and amino acid compositions of carcasses of fish fed live diets showed their efficient consumption. Energy budget analysis of fish fed on the fairy shrimp, S. dichotomus, revealed that about 99.6% of the consumed feed was assimilated with a conversion ratio of 1.59, similar to Artemia (99.4% assimilated with a conversion ratio of 1.44). The presence of carotenoids, high energy content and optimal nutritional value offers the advantages of fairy shrimp as live feed in freshwater aquaculture.