Abstract
This study examined how reducing dietary amino acids (AAs) and apparent metabolizable energy (AME) affects broiler growth and economic return. Two trials were conducted with Cobb 700 and Ross 708 broilers using a randomized design with 12 diet treatments. A 30% AA reduction, compared to the high breeder recommendations for Cobb 700 and Ross 708 strains, reduced body weight in Cobb 700 broilers before 41 days and in Ross 708 broilers at 64 days, while feed efficiency declined in both strains from 0 to 41 days. A 16% AME reduction increased feed intake and worsened feed efficiency in Cobb 700 broilers before 41 days and in Ross 708 broilers from 55 to 64 days. At 55 days, reducing AAs by 20-30% or AME by 8-16% decreased feed cost per kilogram of body weight and improved economic return. However, a 30% AA reduction reduced overall profitability per bird in Cobb 700 broilers at 41 days, while a 16% AME reduction did not. In conclusion, both 30% AA and 16% AME reductions impaired growth, but only excessive AA reduction negatively affected profitability. These findings help optimize feeding strategies for cost-effective broiler production.