We Can Optimize Protein Nutrition and Reduce Nitrogen Waste in Global Pig and Food Production Systems by Adopting Circular, Sustainable, and One Health Practices.

We have exceeded the Earth's carrying capacity to manage the amount of nitrogen (N) waste being generated globally, which can have devastating environmental consequences if immediate action is not taken. Our global food system is a major N user and contributor to N waste. Pork is the most consumed animal-derived protein source in the world, but like other food-producing animals, the N use efficiency of converting dietary protein to edible lean meat is <50%. However, the undigested dietary N is excreted in manure can be recycled by using appropriate manure storage and application methods to crop land to prevent further N losses and emissions to the environment. Therefore, feed and manure, along with animal health and mortality, are the main contributors to N use efficiency in pig production systems. Practical approaches to reduce N losses and emissions to the environment from pig production must be focused on fine-tuning dietary amino acid concentrations to match individual pig requirements, optimizing feed ingredient resource use, upcycling agri-industrial by-products and appropriate sources of food loss and waste, improving manure management, and maintaining pig health.