Nutrition and environmental sustainability

Diet formulation has a direct impact on the efficiency of use of nutrient and energy by the animals and, consequently, on nutrient and waste flow at farm level and their potential environmental impact. The aim of this chapter is to provide an overview of the scientific knowledge regarding the nutritional possibilities to reduce N, P, Cu and Zn excretion by pigs and poultry, as well as emission of ammonia and greenhouse gas and odours, and to describe the means that could be or are already implemented in practice. The main strategies that may be identified are: (1) the improvement of efficiency of nutrient retention in order to reduce excretion and emission from the animals; (2) the modification of chemical properties of excreta in order to reduce the gaseous emissions and the production of odours from manure; (3) the better adaptation of excreta composition to their future use for energy production or as fertilizers, in different strategies of valorisation with or without treatment. Some of these strategies have already been implemented in practice. However, future improvements may still be expected with innovation in feeding techniques, such as precision feeding, and the development of new or improved feed technologies and additives.