Effect of dietary protein and feeding time on growth performance and feed utilization of post larval freshwater prawn Macrobrachium rosenbergii (de Man 1879)

Abstract

A growth trial was conducted to investigate the effect of different dietary protein and feeding times on growth performance and feed utilization of freshwater prawn Macrobrachium rosenbergii Post-Larvae (PL). The experiment was conducted in outdoor concrete pens (6 m-3) for 84 days. Post-larvae with an average weight of 20.8±0.17 mg were stocking at 30 PL m-3 in each pens. Two isocaloric (~15.0 MJ DE kg-1) test diets were formulated to contain two different dietary protein 35 and 40%. The daily feeding level was divided into equal two amounts and fed twice a day at three different feeding times (9:00; 12:00 h); (9:00; 15:00 h) and (9:00; 18:00 h). The highest survival rate, weight gain and specific growth rate (p<=0.05) were observed for PL fed diet with 35% CP. The same trend was observed for PL fed with feeding time 9:00, 15:00 h. The PL fed diet containing 35% protein showed the highest (p<=0.05) protein efficiency ratio, protein productive value, fat retention, energy retention and the better feed conversion ratio. Meanwhile, the PL fed at feeding time 9:00, 18:00 h recorded the better feed conversion ratio. No significant difference was showed for the effect of dietary protein on whole body moisture and protein contents. The highest whole body contents of crude fat and gross energy were observed for prawn fed the diet with 35% CP. However, PL fed at 9:00, 15:00 h had the highest whole body protein and lower fat contents (p<=0.05). Irrespective of dietary proteins or feeding times, M. rosenbergii male recorded the better growth performance and feed utilization than female in all scenarios. The obtained findings revealed that M. rosenbergii PL fed the diet containing 35% CP at feeding time 9:00; 15:00 h is recommended to obtain optimum growth performance and feed utilization.