Use of Cyclop-eeze as a substitute for Artemia nauplii in larval rearing of giant freshwater prawn Macrobrachium rosenbergii (De Man 1879)

Abstract

Four feeding experiments, replacing 25% (T1), 50% (T2), 75% (T3) and 100% (T4), by dry weight, of the live feed Artemia nauplii for Cyclop-eeze, a new larval feed that was claimed to contain the highest known levels of astaxanthin and omega-3 polyunsaturated fatty acids, were compared against a control that was fed with Artemia and egg custard alone, to the larvae of giant freshwater prawn Macrobrachium rosenbergii (De Man 1879). Analysis of different production characteristics of the larvae revealed that the highest survival up to postlarvae (PL) stage was obtained for T2 in which 50% of the Artemia nauplii were replaced by Cyclop-eeze [freeze-dried (FD) deep frozen (DF)], and the highest astaxanthin content of the larval tissue obtained in T4 in which the larvae were fed 100% Cyclop-eeze, although the survival rate was the lowest in this treatment. The costs of different treatments were also compared. The Artemia consumption million−1 larvae was the highest in control (11490 g), followed by T1 (8240 g), T2 (4990 g), T3 (3730 g) and T4, which completely replaced Artemia from stage 5 onwards (1830 g). The highest consumption of Cyclop-eeze million−1 larvae was in T4 (1670 and 10 880 g), followed by T3 (850 and 5560 g), T2 (410 and 2690 g) and T1 (230 and 1490 g) of FD and DF, respectively. The astaxanthin contents of the late-stage larvae fed under the four treatments were 24.90, 27.40, 28.60 and 35.60 μg g−1 tissue for T1, T2, T3 and T4, respectively, while that of the control was 23.70 μg g−1. The lowest cost of live feeds million−1 PL was obtained for T2 (US$ 428.60), followed by T1 (US$ 490.46), control (US$ 529.07) and T3 (US$ 583.26), while it was the highest for T4 (US$ 890.93). The results indicated that Cyclop-eeze could economically replace Artemia nauplii at 50% level that could significantly improve the survival and carotenoid composition of the larvae of M. rosenbergii.