Lysine is an essential α-amino acid used in poultry diets to ensure balanced nutrition and flock performance. The main role of lysine is to participate in protein synthesis and cell growth which confirms its importance for muscle development especially the breast muscle of the chicken. The link between lysine and methionine was confirmed that the response of lysine is influenced by methionine levels in the diet. The deficiency of this amino acid leads to the reduced growth and chick weight.