Rearing of larvae of giant freshwater prawn, Macrobrachium rosenbergii up to postlarvae using different feeds
J.M. ASOKA AND M. HETTIARACHCHI
Ability to produce seed (postlarvae) of giant freshwater prawn, Macrobrachium rosenbergii, for stocking in various culture facilities was a breakthrough in aquaculture in Sri Lanka. However, high cost of Anemia cysts and their occasional scarcity are the major concerns as live Artemia nauplii are considered to be the only suitable larval food for M. rosenbergii. During the present study, a feed for postlarvae of M. rosenbergii was prepared and its performance was evaluated in relation to some other feeds with a view to reduce the use of live Artemia nauplii in the rearing of larvae of this species. No larvae survived beyond the 6th larval stage when they were fed 6 meal's day' with egg custard, egg and mussel meat custard, spray dried algal cells of Schizochytrium sp., a commercially available liquid shrimp feed and the prepared feed separately, each as single feed. The ingredients were 20% powdered milk, 6.8% corn flour, 40% eggs, 30% wet shrimp, 1.0% cod liver oil, 1.0% vitamin mineral mixture, 1.0% agar powder and 0.2% tetracycline. The best feeding regime was 6 meals of Artemia nauplii per day followed by the feeding regime of 3 meals of Anemia nauplii and 3 meals of prepared feed per day when percentage survival (10.35% and 9.28% respectively), mean total length achieved at the end of metamorphosis (9.078 ± 2.828 mm and 7.896 ± 2.812 mm respectively) and time taken to complete metamorphosis by 50% of larvae (40.42 ± 1.38 days and 48.42 ± 2.23 days respectively) were considered, when compared to the two other feeding regimes tested, viz, Artemia nauplii plus spray dried algal cells and Artemia nauplii plus liquid shrimp feed. Therefore, the feeding regime of 3 meals of Artemia nauplii and 3 meals of feed prepared during this study could be recommended in order to reduce the heavy use of costly Artemia nauplii in rearing the larvae of giant freshwater prawn, M. rosenbergii.