为研究饲粮代谢能(ME)、可消化赖氨酸(DLys)水平及其互作效应对21～42日龄肉仔鸡生长性能及血清生化指标的影响,试验采用2×3两因子交叉设计,包括2个ME水平:13.18、12.55 MJ/kg,3个DLys水平:0.80％、0.95％和1.10％,依据理想氨基酸平衡模式配制6种饲粮.选择360只平均体重(718.6±28.6)g的21日龄爱拔益加肉仔鸡,随机分为6组,每组6个重复,进行21 d的饲养试验,期末屠宰,同时测定血清生化指标.结果表明:高ME高DLys组具有最高的平均日增重、平均日采食量和最低的料重比(1.86),饲粮ME和DLys水平对平均日采食量存在极显著的互作效应(P＜0.01)；饲粮ME和DLys水平及其互作效应对屠宰率、全净膛率和腿肌率均无显著影响(P＞0.05).低ME高DLys组胸肌率(30.43％)最高、腹脂率(1.09％)最低,饲粮ME和DLys水平对胸肌率存在显著的互作效应(P＜0.05)；饲粮ME和DLys水平对血清尿素氮含量分别有极显著(P＜0.01)和显著(P＜0.05)影响,对血清谷草转氨酶活性有显著的互作效应(P＜0.05),高ME高DLys组血清尿素氮含量最低.综合生长性能和屠宰性能的分析结果可知,在本试验条件下,对21～42日龄肉仔鸡,饲粮适宜ME和DLys水平分别为12.55 MJ/kg和1.10％ (ME/DLys=1.141 MJ/g).高ME高DLys (ME/DLys=1.198 MJ/g)更利于代谢平衡,减少血清尿素氮含量.%This experiment was conducted to evaluate the effects of dietary metabolizable energy (ME) and digestible lysine (DLys) levels and their interaction on broiler chickens at the age of 21 to 42 days. The experiment was set in a 2 x3 factorial arrangement, diets contained 2 levels of ME (12. 55 and 13.18 MJ/kg) in combination with 3 levels of balanced amino acid (expressed as 0. 80% , 0. 95% and 1. 10% DLys) , three hundred and sixty 21-day-old Arbor Acres broiler chickens with an average body weight of (718. 6·8. 6) g were randomly assigned to 6 groups with 6 replicates per group and 6 birds per replicate. At the end of feeding experiment, birds were slaughtered, and blood samples were assayed for serum biochemical parameters. The results showed that broilers fed the highest ME and Dlys diet had the highest average daily gain and average daily feed intake, and the lowest feed/gain ratio (1.86), and the interaction between ME and Dlys was significant in average daily feed intake (P <0. 01). Levels and the interaction effect of dietary ME and Dlys were insignificant in dressed percentage, eviscerated percentage and leg muscle percentage (P >0.05); broilers fed the lowest ME and highest Dlys diet had the highest breast muscle percentage (30.43% ) and the lowest abdominal fat percentage (1.09% ), and the interaction effect of ME and Dlys was significant in breast muscle percentage (P < 0. 05). Serum urea nitrogen content was significantly affected by dietary ME (P < 0.01) and Dlys levels (P <0.05), serum urea nitrogen content of broilers fed the highest ME and Dlys diet was the lowest, and the interaction effect of ME and Dlys was significant in serum glutamic-oxaloacetic trans-aminase activity (P <0.05). The results of this experiment indicate that broilers can get the optimum growth performance and carcass performance when the level of dietary ME is 12. 55 MJ/kg and the level of dietary Dlys is 1.10% (ME/Dlys = 1.141) from 21 to 42 days of age. However, high dietary ME and Dlys levels (ME/Dlys = 1.198) are more benefit to improve metabolic balance, and decrease serum urea nitrogen content of broilers.
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