Influence of different dietary protein levels and feeding frequencies on growth performance and feed utilization of the Giant freshwater prawn, Macrobrachium rosenbergii with the Nile tilapia, Oreochromus niloticus in polyculture

Abstract

n 84-day experiment was conducted to investigate the effects of two dietary protein levels 30 & 35% CP & three feeding frequencies 2, 3 & 4 times a day (8:0 and 11.0 h), (8.0, 11.0 and 14.0 h) and (8.0, 11.0, 14.0 and 17.0 h) on growth performance and feed utilization of the freshwater prawn, Macrobrachium rosenbergii with the Nile tilapia, Oreochromuis niloticus fry in a polyculture system. The experiment was conducted in small-scale hapas, 3.75 m -3 each in triplicates. Irrespective of polyculture system, prawn PL fed diet containing 35% CP 4 times a day had significant (P≤0.05) the highest final body weight (FBW), weight gain (WG), specific growth rate(SGR) and best feed conversion ratio (FCR) values among all treatments. Meanwhile, the Nile tilapia fed on diet containing 35% CP at 2 times/day recorded the highest significant FBW, WG, and best FCR among all treatments. The highest significant total biomass weight (kg hapa -1 ), and gain (kg hapa -1 ) and feed consumption (kg hapa 1 ) were obtained for prawn and tilapia feed the diet containing 35% protein. No significant differences (P≤0.05) were observed for SGR, FCR and S among all experimental hapas. The same trend was recorded for the different feeding frequencies. The highest values of the whole body CP, EE, ash and gross energy content were recorded for prawn fed on 30% diet at twice per day. No clear trend was observed for body composition of the Nile tilapia fry except for the highest lipid content (P ≤ 0.05) recorded for the fish fed on 30% CP diet 2 times per day. The findings of the current trials revealed that, feeding frequency has a great effect on growth performance and feed utilization efficiency of the freshwater prawn M. rosenbergii PL and the Nile tilapia fry. Feeding frequency 4 times per day for M. rosenbergii PL either 2 or 3 times per day for Nile tilapia fry is recommended under similar rearing condition to achieve best performance for both animals.