Effects of different diets on the ammonia concentration in broiler chicken facilities.

The need to reduce harmful gases emitted from animal housing into the environment has caused adaptations in the means of production and the creation of new models. The aim of this study was to monitor the ammonia concentration in an experimental broiler chicken shed located in the Animal Science Department of the Federal University of Vicosa. There were 800 birds distributed in 40 pens, with 20 birds/pen, submitted to five different diets, which constituted the treatments and the 4 replications: T1 – diet with a high level of protein and a minimum supplementation of amino acids; T2 – diet based on the ideal protein concept; T3 – the T1 treatment plus a diet with Phytase supplementation; T4 – the T1 treatment plus a diet with organic mineral supplementation and; T5 – diet based on combination of the treatments T2, T3 and T4. The monitoring of the ammonia concentration in the different treatments was made with the aid of an instrument (Quest, model Safecheck 100). The statistical analyses were done through regression analysis, performed by a computer program called SAEG, developed by the Federal University of Vicosa (UFV, 2000). The highest ammonia concentrations were detected in the last weeks before slaughter with the highest levels found in T1 and the lowest levels in T2 and T5. These latter two treatments offered a better amino acid profile, facilitating the reduction of nitrogen excretion, which in turn reduced the production of uric acid in the litter and consequently, the emission of ammonia from the litter. Treatments 3 and 4 presented intermediate ammonia values. The addition of Phytase and organic minerals increased the availability of protein to the animal. The highest level of ammonia concentration recommended in installations is 20 ppm. None of the treatments resulted in higher levels of ammonia concentration than the ones allowed for the animals.