Effects of Dietary Amino Acid Level and Duration of Finisher Period on Performance and Carcass Content of Broilers Forty-Nine Days of Age

Abstract

Two studies were conducted to evaluate feeding reduced levels of amino acids (AA) to broilers during the finisher period. Birds grown to 42 days on nutritionally complete diets were fed diets formulated to contain a minimum of 70, 80, 90, 100, or 110% of recommended AA levels for periods of 3, 5, or 7 days prior to slaughter at 49 days of age. Body weight, feed intake, feed utilization, dressing percentage, and abdominal fat content were determined.For finisher periods of 3 to 5 days, a reduction in recommended dietary AA levels may be utilized without impairment of body weight gains of broilers. Extending the finisher period to 7 days resulted in significant (P < .05) reduction of body weight gains on diets with AA levels less than 90% of recommended levels. Feed utilization was more sensitive to reduction in AA levels and may be affected adversely even by a 5-day withdrawal period. Dressing percentage was reduced in some instances, and abdominal fat generally increased when reduced AA levels were fed. The economics of feeding reduced AA levels must be considered in evaluating the results of the present studies.