Two experiments were carried out to evaluate bird performance and nutrient excretion reduction using different nutritional strategies. Eight hundred and 400 male Cobb 500 broilers were housed from 1 to 46 days of age in a poultry house and in metabolic cages, respectively. The following treatments were applied: T1 - normal crude protein level and minimum amino acids supplementation (CP); T2 - protein reduction on ideal protein basis (IP) and amino acids supplementation; 3 — CP diet with phytase supplementation; T4 - CP diet with organic and inorganic trace mineral supplementation; and T5—IP with phytase and organic and inorganic trace minerals. At 46 days of age, treatments did not influence performance, or carcass and breast fillet yields, but T2and T5 promoted higher abdominal fat deposition (P<0.05) as compared to TL All treatments had a quadratic effect (P<0.05) on ammonia air levels as a function of age, with lower levels for the diets formulated on ideal protein basis as compared to thosecontaining regular protein levels. Significant reductions (P<0.05) in nitrogen excretion (12, T5), phosphorus excretion (T3, T5), and manganese excretion (T3, T4, T5) were observed as compared to Tl. Zinc and copper excretion were not different (P>0.05)among treatments. Therefore, the applied nutritional strategies reduced nutrient excretion and ammonia emission, but did not affect broiler performance.
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