The increasing demands of the pork industry is resulting in a higher level of nutrition needed. Often, nutrients are overfed which results in more contaminants such as nitrogen and phosphorus excreted in urine and feces. Nitrogen in particular is important because it emits ammonia and acidifies the environment. Reducing dietary protein content will reduce urinary nitrogen and total nitrogen excretion in grower pigs. Use of fiber sources high in fermentable carbohydrates can shift nitrogen excretion from urine to feces, thereby reducing chances of ammonia emission.

Fine particle size reduces total nitrogen excretion, however, it increases urinary nitrogen excretion. Diets with phytase (an enzyme to make phosphorus usable) results in 4% less total nitrogen excretion than diets without. Using phytase can result in more accuracy in determining phosphorus requirements, which will lower the amount of excess phosphorus that gets excreted in the feces, and lower the cost of production (because phosphorus supplementation is the third most expensive dietary component).