本试验旨在研究饲粮能量水平对42~90日龄嘉积鸭生长性能和屠宰性能的影响，并确定该时期的能量需要量。试验选取健康试验鸭600只，随机分为5组，饲粮能量水平分别为11.30、11.61、11.92、12.24和12.55 MJ/kg，每组4个重复，每个重复30只（公母各占1/2）。对比不同能量组嘉积鸭的生长性能，并使用直线折线模型拟合料重比的能量需要量方程，计算出嘉积鸭最适能量需要量。结果表明：1）饲粮能量水平极显著影响嘉积鸭平均日采食量和料重比（P<0.01），12.24 MJ/kg组料重比最低，显著低于11.30 MJ/kg组（P<0.05）。2）饲粮能量水平极显著影响母鸭体重、体斜长和龙骨长（P<0.01），但对公鸭体尺体重指标无显著影响（P>0.05）；12.24 MJ/kg组母鸭体重及龙骨长显著高于11.30、11.61、11.92 MJ/kg组（P<0.05）。3）饲粮能量水平升高有增加母鸭皮脂率的趋势，其中12.24 MJ/kg组显著高于其他4组（P<0.05），但饲粮能量水平对公鸭屠宰性能指标无显著影响（P>0.05）。4）母鸭12.24 MJ/kg组肌胃指数显著低于11.30、11.61、11.92 MJ/kg组（P<0.05），12.24 MJ/kg组公鸭显著低于11.30 MJ/kg组（P<0.05）。5）通过拟合嘉积鸭能量需要量方程，计算获得其最佳料重比的能量需要量为12.05 MJ/kg。综上所述，12.24 MJ/kg饲粮能量水平能够降低42~90日龄嘉积鸭料重比、提高体重体尺以及皮脂率、降低肌胃指数，是较为适宜的饲粮能量水平；42~90日龄嘉积鸭最适的能量需要量为12.05 MJ/kg。

The aims of the study were to investigate the effects of dietary energy level on the growth and slaughter performances of Jiaji ducks during 42 to 90 days of age and to confirm their optimal energy requirements. A total of 600 healthy Jiaji ducks were selected and divided into five groups (4 repetitions per group and each repetition consisted of 15 male and 15 female ducks). Dietary energy levels were 11.30, 11.61, 11.92, 12.24 and 12.55 MJ/kg, respectively. By comparing the growth performances among different energy groups, the optimal energy requirements for Jiaji ducks were calculated using the equation of evaluating the relationship between the feed to gain ratio and energy levels using broken-line model. The results showed as follows: 1) the average daily feed intake and feed to gain ratio were significantly affected by dietary energy levels (P<0.01), and the feed to gain ratio of Jiaji ducks in 12.24 MJ/kg group was the lowest, which was significantly lower than that in 11.30 MJ/kg group (P<0.05). 2) The body weight, body length and keel length of female ducks were extremely significantly affected by dietary energy levels (P<0.01), however, the body weight and body size of male ducks were not significantly affected by the dietary energy levels (P>0.05). Body weight and keel length of female ducks in 12.24 MJ/kg group were significantly higher than those in 11.30, 11.61 and 11.92 MJ/kg groups (P<0.05). 3) The subcutaneous fat rate of female ducks increased with the increase of dietary energy levels, of which the subcutaneous fat rate in 12.24 MJ/kg group was significantly higher than that in other four groups (P<0.05). However, the slaughter performance of male ducks was not significantly affected by the dietary energy levels (P>0.05). 4) Stomach index of female ducks in 12.24 MJ/kg group was significantly lower than that in 11.30, 11.61 and 11.92 MJ/kg groups, respectively (P<0.05), while that of male ducks in 12.24 MJ/kg group was significantly lower than that in 11.30 MJ/kg group (P<0.05). 5) By fitting the energy requirement equation of Jiaji ducks, the optimal energy requirement was 12.05 MJ/kg. In conclusion, the dietary energy level of 12.24 MJ/kg can decrease the feed to gain ratio and muscular stomach index, and increase body weight, body size and subcutaneous fat rate of Jiaji ducks during 42 to 90 days of age, which is a moderate dietary energy level. The optimal energy requirement for the Jiaji ducks is 12.05 MJ/kg during 42 to 90 days of age.