Lysine Requirements of Female Japanese Quails Base on Performance and Carcass Variables from Twenty-One to Forty-Two Days of Age

The present research was conducted to estimate the dietary lysine (Lys) requirement of growing female quail base on performance and carcass constitutes at 24 to 42 d of age. A dose-response diet mainly based on corn, corn gluten and soybean meal was used. Lys content was minimized in dose-response diet (10 g/kg) while assuring the minimum levels of all other essential amino acids in a manner that would meet or exceed recommendation. This experiment was carried out in a complete randomized design arrangement with 6 dietary Lys level; 10.0, 11.5, 13.0, 14.5, 16.0 and 17.5 g/kg, from 21 to 42 d of age. Each treatment was consisted of 5 floor pens as replicate with 50 quail chicks. As a result of this study increasing dietary Lys level, body weight, body weight gain and feed conversion ratio improved significantly (P < 0.05). Feed intake, carcass weight, breast weight and yield, and thigh weight were significantly (P < 0.05) affected by dietary Lys. The thigh yield at 42 d of age were not influenced significantly (P > 0.05) by dietary Lys. Our results suggested that Lys requirement is 13.5 and 14.7 g/kg when feed conversion, body weight (BW) gain are considered and is at least 13.6 and 15.0 g/kg when and breast and thigh meat properties are taken into account in female Japanese quails at 21-42 d of age for second order polynomial and quadratic broken-line models respectively. These results indicated that the Lys requirement of 13.0 g/kg (total basis) is not ade-quate from 21 to 42 d of age for female Japanese quails. Future research, however, should determine lysine needs for immune system functions of quails reared in conventional environments or during an infectious challenge.