Does feeding more phases reduce ammonia concentrations from broiler litter?

We compared a 3- and 5-phase feeding program in terms of ammonia concentrations measured at litter level, litter composition and quality, nitrogen (N) utilization, performance, welfare, and meat deposition in broilers. A total of 744 Ross 308 male broilers was divided into 2 treatments, each with 6 replicates. The 3-phase diets were formulated to CP and digestible lysine contents of 205 and 11.5 g/kg (0 to 9 d), 195 and 10.8 g/kg (9 to 24 d), and 183.3 and 10.15 g/kg (24 to 39 d), respectively. The 5-phase diets had additional phases from 17 to 24 d and 32 to 39 d with CP and digestible lysine contents of 188 and 10.4 g/kg and 177 and 9.8 g/kg, respectively. Feeding 5 phases reduced the NH(3) concentrations at litter level by 37.95% and 20.81% at 23 (P < 0.05) and 37 d of age (P < 0.05), respectively. There was a tendency for a lower litter total ammoniacal nitrogen concentration for the 5-phase treatment than the 3-phase treatment at 24 and 39 d of age (P < 0.1 for both). Total N concentration of the litter also tended to be lower for the 5-phase treatment at 39 d of age (P < 0.1). The lower NH(3) coincided with a lower average litter pH at 24 and 32 d of age (P < 0.05 for both). Birds fed the 5-phase treatments had a lower incidence of foot lesions at 24 d of age (P < 0.001). Performance as well as carcass yield could be maintained, except for FCR, which was higher for the 5-phase treatment between 17 and 24 d of age and the overall period (P < 0.05 and < 0.001, respectively). The impact of the 5-phase treatment regarding the utilization of N (digestibility, excretion, and retention) was less clear, however the NH(3) volatilized from the litter was significantly reduced. Feeding 5 phases may therefore potentially reduce the NH(3) emitted from broiler houses which has several environmental and health benefits. Although the 5-phase treatment resulted in a significant decrease in feed efficiency, growth performance and meat deposition were maintained.