Effects of varying protein levels on broiler performance when dietary energy levels remain constant

Abstract

In a 9· week long study, three hundred 5-day-old Cobb-100 commercial broiler chicks were fed five isocaloric diets containing 19, 20, 21, 22 and 23 pet cent crude protein respectively. Feed and water were supplied ad libitum. Feed intake, final body weight and body weight gain significantly (P<O.05) increased with increases in dietary crude protein. Feed-conversion efficiency was not significantly influenced by protein level, although birds receiving the 23 per cent protein diet were numerically superior. In addition, protein level did not significantly influence chick mortality and carcass characteristics including dressing percentage, liver, viscera and feathers. Birds on the 21 per cent protein diet gave the best profit over cost of production.