Cultivo multifásico da tilápia nilótica (Oreochromis niloticus,Linnaeus,1757) em tanques-rede, com diferentes regimes de alimentação

Abstract

The evaluation of different regimes of feeding in a multiphases culture of the tilápia Chitralada, Oreochromis niloticus, was made in a period of four months. The aim this experiment was to optimize the regimen of feeding with reduced protein levels in the diverse phases of growth. The tilápias had been cultivated in fifteen useful cages of 4 m3 (2 x 2 x 1,0m), using diets with three levels of crude protein (36, 32 and 28%) in three phases of size (I - 80 300g; II - 300 650g and III - 650 1000g), being therefore, the experimental delineation with protein levels was: control I) 36, 32 and 32%; II) 32, 32 and 32%; III) 32, 32 and 28%. The fishes were fed with ration extruded in different levels of crude protein. Weekly the ration quantity was readjusted according to the feeding rates, the consumption and water quality. Daily it measures temperature, pH, oxygen and transparency. Monthly other variable as ammoniac nitrogen, nitrate, amongst others. Variance analysis was applied - (ANOVA) between the treatments in the different phases, to the level of significance of 5% in the variables of growth and production. The results obtained in phase I had not identified statistics difference (P≤0,05) in the treatments of the diet 36% and 32%PB, occurring only difference for ration of protein efficiency (TPE). In phase II, it was observed statistics differencebetween the fishes, specially on those that had been feed in the previous phase of diet 36% PB (P≤0,05). In phase III, was detected one better performance for the fish that were fed of diet 32% PB. Thus, it concluded that the regime of feeding more efficient for the three size phases is the utilization of the ration extruded with 32% of crude protein.