The nitrogen cycle and loss within a broiler chicken barn: a review

Abstract

Brazilian poultry production has reached unprecedented levels in recent years, especially regarding to the broiler chickens production activity. This increasing productivity is due to progressive implementation of technology in this sector of the animal production in Brazil, which is being mainly focused on improving the animal environment and also, the diets offered to the birds combined with genetic advances. One consequence of high productivity of broiler chickens is the exacerbated production of waste, especially used litter, which has high levels of nutrients, among which is the nitrogen (N), that makes the poultry litter a material with high biological potential to be used as fertilizer. One way of depleting the quality of the litter is through volatilization of N as gaseous ammonia (NH3). The cycling of N for a whole broiler barn has been poorly treated in the current Brazilian scientific literature, which is the reason why this literature review was developed. The aim was to depict all possible sources and sinks and the mechanisms transformation of N inside the barn. Special focus was given to the processes of formation and models of NH3 volatilization. As main conclusion, we observed that the increase in feed conversion ratio with age is one of the factors that contributed to non-utilization of N offered to broilers, implying in a higher concentration of this nutrient in the litter with increasing age and consequently potential of its loss through volatilized NH3.