Abstract
Glycine and serine were determined to be essential for optimum growth in chicks. Chicks fed a chick starter diet for the first 5 days had a requirement of .25% glycine for optimum weight gain for the feeding period of 6-15 days; whereas, chicks fed experimental diets immediately after hatching rquired 1 .0% glycine for a ten-day feeding period. An equimolar amount of serine was found to replace the glycine requirement in chicks. 3-Phosphoglycerate dehydrogenase and phosphoserine phosphatase activity was increased in liver of chicks fed diets with supplemental glycine and serine. The activity of 3-phosphoglycerate was decreased when chicks were fed high levels of serine. 3-Phosphoglycerate dehydrogenase and phosphoserine phosphatase activity were increased in liver of chicks fed 2% protein, 25% protein, and 75% protein diets. The increased activity of phosphorylated enzymes in liver of chicks fed 2% protein diets was completely inhibited by supplementing the diets with cysteine and methionine. The addition of serine and glycine to the low protein diets increased the activity of 3-phosphoglycerate dehydrogenase and phosphoserine phosphatase. Serine transhydroxymethylase activity increased in liver of chicks fed diets supplemented with glycine and also in chicks fed 25% and 75% protein diets. The enzyme activity was decreased in liver of chicks fed diets with supplemental serine. Phosphoserine phosphatase activity was increased in kidney of chicks fed 25% and 75% protein diets, and was the only serine enzyme in the kidney that was influenced by diet. Cyclic 3',5'-AMP increased the liver enzyme activity of 3-phosphoglycerate dehydrogenase and phosphoserine phosphatase. Cyclic 3',5'-AMP had no effect on serine dehydratase activity in chick liver, nor did the 75% protein diets. Serine dehydratase and phosphoserine phosphatase activity in kidney of chicks were two and three fold the amount in hepatic tissues. Serine concentration in blood plasma was increased in chicks fed diets with supplemented serine; whereas, glycine remains at low levels. Glycine and serine in chick plasma were both increased in chicks fed diets with various proportions of glycine. Glycine-glutamate transaminase activity was determined in various organs in chicks. The enzyme activity was about one fourth the amount found in rat tissue. A glycine transaminase was observed in breast muscle which was specific for L-alanine.
Coon, Craig Nelson (1973). The effect of nutrition upon the metabolic enzymes of glycine and serine in Gallus domesticus. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -188810.