Feed-nutrients uptake rates of different weight groups of red tilapia (Oreochromis sp.) in a recirculating aquaculture system

The role of different weight groups of the red tilapia on nutrient uptake of the feed supply was investigated in a recirculating aquaculture system (RAS). Five weight groups of red Tilapia viz. 20 (20±0.0), 40 (39.7±0.44), 80 (80.38±0.41), 120 (113.62±1.92), and 180 (177.67±1.81) g in triplicate treatments were designed. The studied nutrients uptake rates by red tilapia were significantly different ( P <0.05) between the treatments. It was found that the red tilapia could assimilate 11.46% Fe, 13.43% Zn, 6.81% Mn, 3.55% Cu, 26.81 Ca %, 20.29% Mg, 32.53% N, 7.16% K and 15.98% P content of the feed supply during three weeks culture period. The specific growth rate (SGR) and food conversion ratio (FCR) indices showed significant differences ( P <0.05) between the treatments. The highest growth rate was recorded in 120 g treatment. It was concluded that nutrient requirements of the red tilapia are changed in different growth stages.