اثر سطوح مختلف متیونین جیره در دوره رشد بر عملکرد، خصوصیات لاشه، بازده انرژی و پروتئین، ترکیب عضله سینه و برخی فراسنجه ‏های خونی بلدرچین ژاپنی

This research aimed to investigate the effect of different dietary methionine levels on performance, carcass characteristics, energy and protein efficiencies, breast muscle nutrients, and some blood indices in Japanese quails during 11-24 days of age. This experiment was conducted in a completely randomized design during 14 days with 490 quail chicks in seven treatments and five replicates each (14 chicks in each replicate). The experimental diets were the NRC requirement of methionine for quail (0.5 percent), three methionine levels of 7.5, 15, and 22.5 percent lower than that of NRC requirement level (0.4625, 0.425, and 0.3875%, respectively), and three levels higher than that of NRC requirement level (0.5375, 0.575 and 0.6125%, respectively). The results showed that consumption of 0.575% methionine level caused the highest weight gain and lowest feed conversion ratio (linear and quadratic responses). The breast protein content was linearly increased by increasing the methionine level to 0.5%. Consumption of 0.6125% methionine (the highest methionine level) caused the highest relative thigh weight (linear and quadratic responses). The best energy and protein efficiencies were indicated by consumption of 0.575% methionine (linear and quadratic responses). The methionine requirement for optimal weight gain, feed conversion ratio, and energy and protein efficiencies were 0.569, 0.578, 0.54, and 0.35% according to the quadratic broken line. In total, the level of 0.569% was determined for methionine requirement based on the cumulative response of weight gain, feed conversion ratio, and energy and protein efficiencies.