511 - Late-Breaking: Dietary Glycine Supplementation During Growing and Finishing Phases Increases Body Weight and Improves Meat Quality of Intrauterine Growth Restricted Pigs

Glycine is required for maximum growth and development for growing pigs. Traditional swine diets are deficient in glycine. This is concerning for intrauterine growth restricted (IUGR) pigs (20-25% of all pigs born) as they are born with low bodyweights and underdeveloped skeletomuscular systems. Therefore, IUGR piglets are culled at birth, as they are unlikely to survive and unable to reach market weight at the same rate as normal birthweight (NBW) littermates. Additionally, IUGR pigs are not fed to market weight due to undesirable carcass attributes at slaughter such as increased subcutaneous fat deposition and decreased overall desirable protein yield. This study was designed to test the hypothesis that providing dietary glycine supplementation in traditional corn- and-soybean meal-based diets would improve the growth rate of IUGR pigs between weaning (age 21d) and market weight (age 188d). Fourteen IUGR pigs (birthweight = 0.98±0.03 kg, mean ± SEM) and 20 NBW pigs (birthweight = 1.44±0.02 kg, mean ± SEM) were obtained at weaning and used for this study. Pigs from each birthweight group were randomly assigned to 1% glycine + 0.19% corn starch treatment group or 1.19% alanine group (isonitrogenous control). Data were analyzed by using 2-way ANOVA and Duncan multiple comparison test. At 188 d of age, glycine supplemented IUGR pigs  were 4.4 kg heavier (P < 0.05) than control IUGR pigs, and had similar (P >0.05) body weights to those NBW counterparts. Feed intake did not differ among the treatment groups (P >0.05). Additionally, glycine supplementation improved markers of meat quality in IUGR pig carcasses compared to control IUGR carcasses, including decreased backfat thickness, increased loineye area, and increased overall muscle score (P < 0.05). Overall, results of this study show that dietary glycine supplementation to IUGR pigs post-weaning has positive effects on lean tissue gain and meat quality. (Supported by USDA-NIFA)