. Excessive feeding of protein feed results in increased nitrogen excretion from pigs; 2. Diets and nutrient levels are too high, protein digestibility is affected, which in turn affects the pollution index of pig manure; 3. Farmers lack scientific knowledge and insufficient raw materials 1. The lack of equipment results in unscientifically configured feed, inadequate feed nutrition, and feed quality cannot be guaranteed. Not only can its production performance not be fully utilized, but it also pollutes the environment