PSXIII-20 Low birth weight pigs gain muscle more efficiently than normal birth weight pigs when limit-fed sow milk replacer formula

Abstract

Abstract Postnatal muscle growth is impaired in low birth weight (LBWT) neonatal pigs. Dietary leucine supplementation has been established as a dietary intervention to enhance muscle growth in growing animals. The aim of this study was to investigate the efficacy of supplementing LBWT neonatal pig diets with branched-chain amino acids (BCAA) to enhance the rate of protein accretion. Twenty-four pigs were housed in individual cages starting at 1 d of age. LBWT and normal birth weight (NBWT) were defined when birth weight was 2 SD below or within 0.5 of the litter average. Each LBWT pig was matched with a NBWT same sex littermate and assigned to either the control diet or supplemented with 1% BCAA in a 2×2 factorial arrangement. Diets were isocaloric, isonitrogenous and met NRC requirements. Pigs were fed 250 ml/kg BW/day of control or BCAA sow milk replacers. Carotid and jugular catheters were surgically placed on day 21 for blood sampling. Body composition was measured by dual x-ray absorptiometry on day 0 and 28. On day 29, blood samples were taken over 4 h following a meal. Data were analyzed using MIXED procedure of SAS version 9.4. Plasma leucine, isoleucine, and valine concentrations were greater in pigs fed BCAA (P < 0.001). LBWT pigs had lower weight gain (P < 0.001), average daily gain (P < 0.01), and feed conversion (P < 0.0001), and accreted protein more efficiently (P < 0.0001) than NBWT pigs regardless of diet. Although BCAA supplementation had no effect, these data suggest that LBWT pigs grow leaner and more efficiently than NBWT pigs when limit-fed.