A total of 84 barrows and females from a commercial hybrid (Agroceres × MS60), averaging 15.3 kg, was raised from 15 to 35 kg to evaluate the effect of different dietary levels of metabolizable energy (ME) and crude protein (CP) formulated according to the ideal protein concept and phytase supplementation on performance and carcass characteristics. The experiment was analyzed as a complete randomized block design, in a factorial arrangement of treatments 3 × 2 + 1, with three ME levels (3,080, 3,230, and 3,380 kcal/kg), two of CP (14% and 16%), supplemented with synthetic amino acids and 1000 FTU/kg of phytase, with calcium level reduced by 25% and phosphorus by 30%. Additional control treatment was formulated with 18% CP and without phytase, to attend the nutrient requirements of pigs according to Brazilian Feedstuffs Tables recommendations. Therefore, seven treatments, six replications and two animals per experimental unit were used. No treatment effect on daily weight gain, feed conversion, daily ME intake and weight of organs (absolute and relative) of pigs was observed.Feed intake was higher and fat deposition rate, lower in pigs fed diet with 3,380 kcal ME/kg. Decreasing nitrogen intake, increasing efficiency of nitrogen utilization for gain and lower blood urea content were observed for pigs fed 14% CP diets compared to those with 18%. The reduction of levels of ME, CP, available phosphorus and calcium to 3,080 kcal/kg, 14%, 0.54% and 0.28%, respectively, in rations for pigs, formulated based on ideal protein concept and phytase, do not affect performance of pigs from 15 to 35 kg.
amino acids; enzyme; nutrition; performance; swine
