Abstract

One of the attributes of amino acid lysine is to manufacture muscle protein, as it is a physiologically essential amino acid for immunity, development and production in birds. This study evaluates the influence of several levels of the essential amino acid lysine for chicks, with age of about 504 hours, maintained at a temperature of approximately 29 degrees Celsius. The basal diet contained 21.0% crude protein and 3,000 kcal of energy of biological transformations/kg. This formula was supplemented with levorotatory-lysine acid monohydrochloride, resulting in diets with 1.040 to 1.280% of total lysine for five experimental treatments. The treatments were found to have a mathematical expression squared influence on animals’ weight gain, conversion of diet, total liver mass and protein synthesis index. The effect of the five experimental treatments was not observed in diet consumption, fat synthesis index, absolute weights of intestines and heart, and percentage of liver mass. It was concluded that the total lysine requirements for chicks aged up to 504 h were 1.240%.

Key words: Thermal environment, dietary lysine, growth performance, rearing setting.