عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The present research was conducted to estimate the dietary lysine (Lys) requirements of growing quails as based on performance and carcass constituents parameters at 3 to 24 d of age. The experiment was carried out in a complete randomized design arrangement the 6 dietary Lys levels; 1, 1.15, 1.30 (NRC 1994), 1.45, 1.60, and 1.75 %, from 3 to 24 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 (1%) while assuring the minimum levels of all other essential amino acids in a manner that would meet or exceed NRC (1994) recommendation. Each treatment consisted of 5 floor pens as replicate with 50 quail chicks. Second order equation methods were utilized for determining the optimum dietary Lys levels. With increase in dietary Lys, body weight, body weight gain and feed conversion ratio improved significantly (P < 0.05). In female Japanese quail, carcass and breast weights were significantly (P < 0.05) affected by dietary Lys. While dietary Lys has no significant effect on thigh weight, carcass and breast yields in female quails (P > 0.05), in male quails, Carcass, breast, thigh weights as well as yields are significantly affected by Lys level, during the birds 3-24 d of age (P < 0.05). Lys needs based on second order equation method when mixed performance parameters taken as response of Lys requirement were recorded as 1.48% at 3-24 d of age. The data suggested that total Lys requirement could be estimated based on second order equation method as 1.48, 1.54% respectively for female and male quails when carcass constitutents are considered at the birds 24 d of age. These results indicate that the NRC (1994) Lys requirement of Lys 1.30% (total basis) is not adequate from the birds 3 to 24 d of age for optimum performance in the case of Japanese quails.