THE EFFECT OF DIETARY CRUDE PROTEIN ON GROWTH, AMMONIA CONCENTRATION,AND LITTER COMPOSITION IN BROILERS

An experiment was conducted to determine the effect of diets with redu ced CP and supplemental amino acids on broiler performance, N excretio n, litter characteristics, and equilibrium NH3 gas concentration. Resu lts suggest that reducing CP (and lysine) below 241 g/kg (13.7 g/kg ly sine) in the diets fed during the first 3 wk may slightly increase fee d:gain and therefore may not be advisable. During the period 22 to 43 d of age there were no significant differences in weight gain and BW a t 6 wk of age when reducing CP from 215 g/kg (11.5 g/kg lysine) to 196 g/kg (11.3 g/kg lysine), but feed intake and feed:gain ratio increase d. However, reducing CP did cause equilibrium NH3 gas concentration an d litter N to decline by 31 and 16.5%, respectively. Both of these adv antages will improve air quality within the housing facility and possi bly reduce heating costs during winter associated with higher ventilat ion rates required to reduce elevated NH3 gas concentrations.