215 - Effects of Reducing Crude Protein with Supplementation of Six Essential Amino Acids and Glutamate on Growth and Backfat of Finishing Pigs

This study evaluated the effects of low CP diets on growth performance of finishing pigs. Seventy-two pigs (54 kg BW) were allotted to 3 treatments (8 pens/treatment) based on RCBD with sex and initial BW as blocks. Pigs were fed for 56 d until 120 kg BW based on 3 phases (P1/2/3 for 21/17/18 d, respectively). Treatments were CON (18.0, 13.8, 12.7% CP for P1/2/3; supplementing Lys, Met, Thr, and Trp); LCP (13.5, 11.4, 10.4% CP; supplementing Lys, Thr, Trp, Met, Val, and Ile); and LCPG (14.1, 12.8, 11.1% CP; LCP + Glu to match % Glu with CON). All diets met NRC requirements and had 2.6 Mcal/kg NE. Growth performance and backfat thickness were measured by phase. At d 56, blood and fecal samples were collected to analyze blood parameters and fecal microbiota. Data were analyzed using SAS 9.4. Overall, the growth performance and backfat thickness did not differ among treatments. BUN of LCPG was lower (P < 0.05) than CON (4.03 to 6.05 mg/dL), whereas the insulin of LCPG was greater (P < 0.05) than CON (222 to 116 pmol/dL). Relative abundance of Streptococcaceae in CON (6.1%) was greater (P < 0.05) than LCP (2.0%) and LCPG (2.3%), whereas the abundance of Erysipelotrichaceae of CON (1.8) was greater (P < 0.05) than LCP (0.9%). Colectively, when Lys, Thr, Trp, Met, Val, and Ile were provided sufficiently and NE was maintained, CP can be reduced by 2.6% without affecting growth performance and backfat thickness compared to conventional diets with Lys, Met, Trp, and Trp. Feeding low CP diets reduced harmful bacteria, and Glu supplementation further enhanced nitrogen utilization and glucose metabolism. Application of low CP formulation with supplementation of 6 essential amino acids to finishing pigs can be successful, when NE is matched and further beneficial with Glu supplementation.