A complete review of the diets manipulation in order to minimize the impacts of swine production on the pollution is done. For copper and zinc, the concentrations in the diet should aim the minimum requirement levels so their excretion in the pig manure should not be a concern. A wide variation in P and N retention efficiency can be observed between farms and can comes from different sources: feed wastage, the availability of N and P, the minimum amounts of N and P required by the animals and the differences between the pigs’ requirements and the levels of P and N available in the diets. To improve the efficiency of P two main measures can be taken: to improve and better assess P availability and to feed the animal closer to its requirements. Reductions in the available P allowances will result in less P excreted by the pigs in their manure and also lower feed costs. 10% less P intake leads to a reduction of at least 15% of P in the manure. To improve the efficiency of N utilization two main measures can also be taken: improve the amino acid (AA) balance in the diet (as almost half of the N excretion could be attributed to a poor AA balance in the diet) and to feed lysine closely to the pigs requirements and to assess the availability of lysine in feedstuffs. A reduction of 10% of the crude proteins level results in a reduction of N of at least 15%. Management practices can considerably improve the mineral balance on farm animals such as phase and split-sex feeding, minimizing feed wastage and a good health status. However more precision in feed evaluation, feed formulation manufacturing and delivery to the animal is also needed to improve situation.

The situation of the measures available to lower the impact of the pigs diets on the environment is well presented and documented. Phytase and lysine are tools to improve the situation but management measures are also the key to the reduction of the pollution from an unbalance nutrient cycle.