Dietary N-Carbamylglutamate Supplementation in a Reduced Protein Diet Affects Carcass Traits and the Profile of Muscle Amino Acids and Fatty Acids in Finishing Pigs

The aim of this study was to investigate whether dietary N-carbamylglutamate (NCG) supplementation in a reduced protein diet affected carcass traits and meat quality in finishing pigs. A total of 120 gilts were randomly assigned to one of four treatments for 40 days, including a standard protein diet (SP), a reduced protein diet supplemented with 1.7% l-alanine (RP + Ala), a reduced protein diet supplemented with 1.0% l-arginine (RP + Arg), and a reduced protein diet supplemented with 0.1% NCG and 1.7% l-alanine (RP + NCG). NCG supplementation increased the endogenous synthesis of l-arginine. The RP + NCG diet significantly increased the loin eye area (p < 0.05) and tended to decrease the 10th rib fat depth (p = 0.08). NCG supplementation in a reduced protein diet was effective to produce functional pork with a high content of leucine (p < 0.05). The composition of several ω-6 and ω-3 polyunsaturated fatty acids (PUFAs) but not the ratio of ω-6/ω-3 PUFAs in muscles was altered in finishing pigs with dietary NCG supplementation. In conclusion, the RP + NCG diet is effective to increase the longissimus dorsi muscle area, decrease back fat accretion, and produce functional pork with a high content of leucine but without a negative impact on the muscle fatty acid profile in finishing pigs.