Research Progress on the Application of Low Protein Diets in Pigs at Different Growth Stages

The shortage of protein feed resources, low feed utilization rate and pollution problems have restricted the development of livestock and poultry breeding industry. Low protein diets balanced with synthetic amino acids could reduce the use of protein materials such as soybean meal, improve feed utilization rate, and be benefit to sustainable development of the breeding industry. The application of low protein diets in pigs at different growth stages were summarized in this article. Based on the previous studies, it was found that low protein diets prepared with metabolizable energy and digestible energy feeds were prone to cause carcass to become fat, and a net energy-based diet formulation method was recommended. Reducing the protein level of 1%-4% could improve the growth performance of pigs in each growth stageto some extent, and the effect of reducing nitrogen emission was remarkable. However, the protein content in the diets of piglets and sows should not be too low, and a reduction of 1%-3% in low protein diets was suggested in most studies. The addition of branched- chain amino acids L-Leu, L-Val and L-Ile in low protein diets was beneficial to the improvement of growth performance and immune performance of the organism. Finally, based on these studies, issues related to the current research and application of low protein were discussed in this paper. It is believed that low nitrogen diets have broad application prospects.