The available lysine requirements of 7-9 week old sexed broiler chicks.

The experiments were conducted to determine the available lysine requirement of broiler chicks during the 7-9 week growing period. The chicks were sexed at day old, and the sexes were reared in separate pens in the same facility. Commercial-type broiler rations were fed from day old to 7 weeks of age. At 7 weeks the sexing errors were removed and the pens equalized to 50 birds per pen. The eight dietary treatments were replicated three times per sex. Graded levels of L-lysine-HCL were added to the basal ration to give a stepwise increase of 0.07% lysine per level. The available lysine requirement for female during the 7-9 week period was 0.64% for both growth and feed conversion. When this was expressed as a function of energy, 0.187% available lysine per megacalorie of metabolizable energy (M.E) per kg. of diet was required. The available lysine requirement for males during this period was 0.69 and 0.66% for gain and feed conversion, respectively. Expressed as available lysine per megacalorie of M.E. per kg. of diet, the values would be 0.202 and 0.193%, respectively.