Estimation of optimal lysine in quail chicks during the second and third weeks of age
An experiment was conducted to assess the optimal levels of dietary lysine (Lys) in Japanese quail from 7 to 21 days of age. A dose-response diet was formulated to be adequate in all amino acid concentrations with the exception of Lys. Different levels of supplemental L-Lysine.HCl were added to the doseresponse diet at the expense of corn starch, sodium bicarbonate, and NaCl to create 6 levels of Lys ranged from 0.91% to 1.51% in diet. Optimal Lys for feed conversion ratio, breast meat yield, and leg meat yield were estimated at 1.15%, 1.21%, and 1.16% of diet, respectively, based on linear broken-line regression. With quadratic broken-line regression, the Lys requirements for body weight gain, feed conversion ratio, thigh meat yield, and breast meat yield were estimated at 1.27%, 1.21%, 1.32%, and 1.34% of diet, respectively. Overall, Lys requirements of starting Japanese quail may be at least 1.34% of diet for optimizing carcass attributes fed low-CP dose-response diet.