Protein Synthesis Is Impaired in Low Compared to Normal Birth Weight Neonatal Pigs

Abstract

Postnatal growth is reduced in low (LBWT) compared with normal birth weight (NBWT) pigs. The objective of this study was to determine body growth and muscle protein deposition in LBWT and NBWT neonatal pigs. Newborn female pigs (n = 6) were considered NBWT or LBWT when birth weight was within ± 0.5 and -2 SD of litter average. NBWT pigs were fed a control diet, while LBWT pigs were fed an equal amount per kg body weight of either the control diet or the same diet supplemented with 0.68% branched-chain amino acids (BCAA) for 21 d. On day 21, pigs were infused with [2H5]phenylalanine for 8 h, and plasma taken during the last 4 h of tracer infusion. Weight gain was lower for LBWT compared with NBWT pigs throughout the study (P < 0.05). Fat and lean deposition measured by Dual-energy X-ray absorptiometry were lower (P < 0.05) in LBWT compared with their NBWT siblings. Feed conversion and protein efficiency were not different among all groups; however, the efficiency of energy deposition in LBWT pigs was about...