The effect of feeding various levels of dietary glycine in a pre-experimental diet to one-day old chicks on their subsequent glycine plus serine requirement.

Two experiments were conducted to determine the effect of feeding chicks 1=9 days of age various levels of clycine in corn-casein and corn-soybean-corn gluten meal diets upon the subsequent glycine plus serine requirement of chicks during the remaining 10-21 day feeding period. Chicks in Experiment 1 fed corn-casein basal diets with 1.3% additional dietary glycine (2.15% total glycine plus serine) gained significantly (P less than or equal to 0.01) more weight during an initial 9-day feeding period than chicks fed basal diets with 0.3% and 0.9% supplemental glycine. Chicks fed the 2.15% glycine plus serine diets during the first 9 days posthatching and then fed basal diets containing 0.3% supplemental glycine (1.15% total glycine plus serine) for a 10-21 day feeding period gained weight equivalent to chicks fed 2.15% glycine plus serine diets for the entire 21-day period. The corn-casein basal diet contained 21.0% protein and 0.85% glycine plus serine. Chicks in Experiment 2 fed corn-soybean-corn gluten meal diets containing 1.8% glycine plus serine did not respond to glycine supplementation druing the initial 9-day feeding period or the 10-23 day feeding period. The results suggest feeding optimum levels of glycine to chicks during the first nine days after hatching decreases the requirement of glycine and serine during subsequent feeding periods.