Low-cost diet for monoculture of giant freshwater prawn (Macrobrachium rosenbergii de Man) in Bangladesh

Abstract

An experiment was conducted for 3 months in 12 experimental ponds, each of 30 m 2 , with a view to develop a low-cost diet for monoculture of Macrobrachium rosenbergii in ponds. Three experimental diets (30% protein) were formulated using ¢sh meal, meat and bone meal, mustard oilcake, sesame meal and rice bran in diierent combinations partially replacing ¢sh meal by meat and bone meal and sesame meal and assigned to treatments T1, T2 and T3 respectively. A commercial golda feed (Starter-III) was assigned to T4 (reference diet). Each treatment had three replicates. Juveniles of M. rosenbergii (2.90 � 0.21g) were stocked at the rate of 40 000 ha � 1 . Prawns were fed three times daily at the rate of 10% and 5% of their body weight at the beginning and for the last 2 months respectively. The ponds were provided with aeration during the night using air pumps. The ranges of water quality parameters recorded in diierent ponds were: temperature 28.9^32.51C, dissolved oxygen 5.1^ 8.1mg L � 1 and pH 6.4^7.7. The results showed that the weight gain of prawns fed diet 1 was signi¢cantly higher (Po0.05) than those fed diets 2 and 3, but was not signi¢cantly diierent from those fed diet 4 (reference diet). The feed conversion ratio (FCR) values of diets ranged between 2.21 and 2.96 with diets 1 and 4 showing signi¢cantly lower (Po0.05) FCR values. The survivals (%) ranged between 68% and 78% with prawns fed diets 1 and 4 showing signi¢cantly higher survival. The production of prawn ranged between 921 and 1428 kg ha � 1 and diet 1 resulted in a signi¢cantly high (Po0.05) production. A simple economic analysis showed that diet 1 generated the maximum net pro¢t of Tk 159178 ha � 1 . The results of the study showed that a diet containing 20% ¢sh meal,10% meat and bone meal,15% mustard oilcake, 15% sesame meal, 35% rice bran, 4% molasses and 1% vitamin^mineral premixes may be recommended to the farmers for monoculture of M. rosenbergii in ponds.