本试验以低胆碱、低蛋氨酸饲粮为基础饲粮,通过两因子二次回归正交旋转组合设计,对21~42日龄肉仔鸡胆碱和蛋氨酸需要量进行研究。试验选用21日龄爱拔益加(AA)肉仔鸡480只,随机分为12个组,其中1~8组为试验组,9~12组为中心组,每组4个重复,每个重复10只鸡,公母各占1/2。分别以胆碱和蛋氨酸为自变量,以反映肉仔鸡生长性能和屠宰性能的各项指标为因变量拟合回归方程,估计21~42日龄肉仔鸡胆碱和蛋氨酸的需要量。试验期21 d。结果表明:胆碱和蛋氨酸水平对21~42日龄肉仔鸡的平均日采食量、料重比、腹脂率和肝脂率有显著影响(P<0.05)。当胆碱水平在860~1 120 mg/kg时,肉仔鸡平均日采食量随着蛋氨酸水平的增加而升高,蛋氨酸水平增至0.40%后,继续增加对平均日采食量的改善作用不明显;蛋氨酸水平在0.35%~0.42%,胆碱水平在860~1 120 mg/kg时,肉仔鸡的料重比达到最低值;蛋氨酸水平在0.30%~0.47%时,随着胆碱水平的增加肉仔鸡腹脂率呈下降趋势;当蛋氨酸水平在0.30%~0.40%,胆碱水平在1 000~1 400 mg/kg时,肉仔鸡肝脂率随着胆碱水平的增加和蛋氨酸水平的降低呈下降趋势。在本试验条件下,当胆碱水平为990~1 030 mg/kg,蛋氨酸水平为0.40%~0.43%时,肉仔鸡可达到最佳生长性能;当胆碱水平为1 780~1 880 mg/kg,蛋氨酸水平为0.37%~0.38%时,肉仔鸡可达到最佳屠宰性能。

A research on choline and methionine requirements for broilers aged 21 to 42 days were carried out. A total of 480 Arbor Acre broilers aged 21 days were divided into 12 groups (4 replicates per group and each replicate had 10 broilers) in random. Groups 1 to 8 were experimental groups, and groups 9 to 12 were center groups. A diet with low levels of choline and methionine was used as the basal diet in this experiment. To study the influence of different choline and methionine levels on growth performance and slaughter performance, a two-factor combinational design of quadratic regression and orthogonal rotation was used. The experiment lasted for 21 d. The results showed that choline and methionine levels had significant effects on average daily feed intake (ADFI), feed/gain (F/G), abdominal fat percentage and liver fat percentage of broilers aged 21 to 42 days (P<0.05). When choline levels were from 860 to 1 120 mg/kg, ADFI was increased with the rise of methionine level, until the methionine level added at 0.40%. When methionine levels were from 0.35% to 0.42% and choline levels were from 860 to 1 120 mg/kg, F/G was minimum. When methionine levels were from 0.30% to 0.47%, abdominal fat percentage was decreased with the rise of choline level. When the levels of methionine were from 0.30% to 0.40% and choline levels were from 1 000 to 1 400 mg/kg, the liver fat percentage was decreased with the increasing choline level and the reducing methionine level. In this experiment, choline and methionine requirements for optimal growth performance of broilers aged 21 to 42 days are from 990 to 1 030 mg/kg and from 0.40% to 0.43%, respectively. For optimal slaughter performance, choline and methionine requirements are from 1 780 to 1 880 mg/kg and from 0.37% to 0.38%, respectively.