Oral N‐carbamylglutamate (NCG) supplementation increases growth rate in sow‐reared pigets

Abstract

Oral supplementation of NCG, an analogue of N-acetylglutamate, increases plasma arginine concentrations and growth rate in sow-reared piglets. To investigate the mechanism involved in this growth response, nursing piglets (n = 18; BW = 3.19 kg) were orally administered 0 or 50 mg/kg BW of NCG twice daily from 9 to 16 d of age. On d 17, piglets were intragastrically fed sow’s milk at a rate of 7.5 ml/kg, with the respective NCG treatment at time 0 and 60 min, then given an i.v. flooding dose of [3H]phenylalanine to measure protein synthesis. At 90 min, the piglets were euthanized and tissue samples were collected. NCG-treated pigs gained 25% more weight during the 8-d trial than control pigs (1.93 × 0.07 vs. 1.55 × 0.10 kg, respectively; P < 0.01). Tissue mass and protein synthesis rate of longissimus dorsi were 16% and 20% greater respectively, in NCG-treated pigs compared to control pigs; however, these increases did not reach statistical significance. NCG-treated pigs had 29% higher plasma insulin concentrations at 90 min compared to control pigs, but this difference was not statistically significant. Plasma arginine concentrations were 32% higher in NCG-treated pigs compared to control pigs at 90 min (P < 0.05). Although the exact mechanism has not been delineated, it appears that oral NCG administration increases plasma arginine levels leading to an increase in growth rate of nursing piglets. (NIAMS AR 44474, USDA 58-6250-6-001, and USDA/NRI #2003-35206-13694). Pigs, N-carbamylglutamate, Protein synthesis