Fairy Shrimp (Streptocephalus sirindhornae) as Live Feed Improve Growth and Carotenoid Contents of Giant Freshwater Prawn Macrobrachium rosenbergii

We evaluated the potential of adult fairy shrimp, Streptocephalus sirindhornae, as live food for growth and enhancing the carotenoid contents in the giant freshwater prawn Macrobrachium rosenbergii. Completely randomized cultures of 6-months-old prawns were treated individually with 5 different food ratios (adult fairy shrimp to dry shrimp diet; 0: 100, 25: 75, 50: 50, 75: 25 and 100: 0) for 60 days in circular black plastic containers containing 20 L of water. The diet was fed at a rate of 3% of the prawn body weight per day. Each food concentration was experimented with 12 replicates and the whole experiment (5 treatments) using a total of 60 individuals. The results showed that the initial lengths (11.9-13.0 cm) and weights (23.20-31.65 g) of the experimental prawns with the 5 food ratios were not significantly different. However, length (0.87 cm) and weight (15.14 g) gains of the prawns fed pure fairy shrimp treatment (100: 0) were significantly different from those of the other dietary treatments (p<0.05). The prawns fed with the pure fairy shrimp had the highest specific growth rate of 0.84%, the lowest food conversion ratio of 1.38 and the highest survival rate of 84.75%. The prawns fed with pure fairy shrimp contained the highest total carotenoids of 4.144 g g-1 of fresh weight with large amounts of astaxanthin and -carotene, which was 2.8 times of those fed with pure dry diet treatment (p<0.05). Present results indicate improved growth performances and elevated carotenoid contents of prawns suggesting fairy shrimp as promising feeds in freshwater aquaculture.