Influence of Energy Level and Glycine Supplementation on Performance, Nutrient Digestibility and Egg Quality in Laying Hens (Report‪)‬

INTRODUCTION Amino acids are utilized by poultry to fulfill a diversity of functions. Amino acids are constituents of structural and protective tissues such as skin, feathers, and bone as well as soft tissues like organs and muscles (NRC, 1994). In addition, amino acids may serve a variety of metabolic functions and as precursors for many important non-protein body constituents. There are at least 20 amino acids in body proteins and all are physiologically essential (NRC, 1994). However, some amino acids can be synthesized by using carbon skeletons and amino groups derived from other amino acids present in the diet in excess of requirements. Amino acids synthesized in this manner are termed nonessential. Amino acids that cannot be synthesized or cannot be synthesized at a sufficient rate to permit optimal growth or reproduction are termed essential (NRC, 1994).