Effects of Dietary N-Carbamylglutamate Addition with Two Different Levels of Crude Protein (Low and High) on the Growth, Nitrogen Retention, Amino Acids in the Carcass, Blood Health, Gut Bacteria, and Meat Quality of Finishing Pigs

Abstract

Simple Summary Lowering the dietary crude protein (CP) content by 1–4% in finishing pigs, when appropriately paired with restricting amino acids, enhances feed efficiency and decreases nitrogen excretion without negatively affecting performance. Adding 0.05–0.1% N-carbamylglutamate (NCG) to these low-protein diets addresses potential protein deficiencies by promoting arginine synthesis, fostering muscle growth, and improving nitrogen utilization. This study investigated the optimum level of two different crude protein densities (low and high) and dietary N-carbamylglutamate supplementation on finishing pigs’ performance, blood profile, gut health, and meat quality. Low-protein diets (13% CP) improved nitrogen retention, blood parameters (blood urea nitrogen, BUN), and carcass amino acids, while 0.1% NCG supplementation improved gut health, and meat quality in finishing pigs. Lowering protein levels is beneficial for improving nitrogen retention and blood parameters, and supplementing with 0.1% NCG can improve gut health and meat quality. In conclusion, a combination of a low-protein diet (13% CP) and 0.1% NCG supplementation is an effective strategy to improve carcass characteristics, blood parameters, gut health, and nitrogen utilization without detrimental effects on performance in finishing pigs.