2～3周龄天府肉鸭净能需要量的评定

Evaluation of Net Energy Requirement of Tianfu Meat Ducks Aged from 2 to 3 Weeks

本试验旨在测定2-3周龄天府肉鸭的净能（NE）需要量。选取7日龄天府肉鸭300只,其中50只随机分为自由采食组和15%、25%、35%、45%限饲组,进行代谢试验,测定不同饲喂水平下饲粮的表观代谢能（AME）。另外250只用于饲养试验和比较屠宰试验。试验开始前选取10只用于初始体成分的测定,其余240只随机分为5个组（同代谢试验）。14日龄时,从自由采食组选10只屠宰,测定试验中期试验鸭体成分;21日龄时,从每个组选10只屠宰,测定试验末期试验鸭体成分。根据自由采食组和限饲组饲粮的AME和试验鸭的生长性能、体成分,获得试验鸭在不同饲喂水平的产热量（HP）和代谢能摄入量（MEI）,建立MEI和log10HP间的回归方程,外推到MEI为0时的HP即为维持净能需要量（NEm）;根据自由采食组试验鸭在3个阶段的机体总能量（BE）和体重（BW）,建立二者间的回归方程,方程的斜率为生长净能需要量（NEg）。结果如下：不同饲喂水平间,天府肉鸭的饲粮AME、平均日采食量（ADFI）、平均日增重（ADG）、料重比（F/G）、体脂肪、体蛋白、体能量、以脂肪形式沉积的能量（REf）、以蛋白质形式沉积的能量（REp）、MEI、沉积能（RE）和HP均存在显著差异（P〈0.05）。限饲组肉鸭的饲粮AM E、F/G、体蛋白和体水分显著高于自由采食组（P〈0.05）,ADFI、ADG、体脂肪、体能量、REf、REp、MEI、RE和HP却显著低于自由采食组（P〈0.05）。2-3周龄天府肉鸭MEI和log10HP间的回归方程为：log10HP=2.76＋0.000 1×MEI,BW与BE的回归方程为：BE=-768.87＋10.71×BW。由此可见,2-3周龄天府肉鸭的NEm为577.03 k J/（kg BW0.75·d）,NEg为10.71 k J/g,2-3周龄天府肉鸭NE需要量的析因模型为：NE=577.03BW0.75＋10.71△W。

The objective of this study was to determine the net energy（ NE） requirement of Tianfu meat ducks aged from 2 to 3 weeks old. A total of 300 seven-day-old Tianfu meat ducks were selected for the experiment.To determine the apparent metabolizable energy（ AME） of diets at different feeding levels,fifty ducks were selected and randomly distributed into five feeding levels consisting of ad libitum and 15%,25%,35%,45%restriction groups. The remaining 250 ducks were used for the feeding experiment and comparative slaughter experiment. At the beginning of the experiment,ten ducks were selected and slaughtered to determine the initial body composition. The remaining ducks were randomly distributed into five feeding treatments（ same as the metabolic experiment）. At the age of 14 days,ten ducks were selected from the ad libitum group and slaughtered to determine the body composition; at the age of 21 days,ten ducks were selected from every treatment and slaughtered to determine the final body composition. Based on the data of AME of diets,growth performance and body composition of ducks of the ad libitum group and restriction groups,heat production（ HP） and metabolizable energy intake（ MEI） at different feeding levels were obtained. NE for maintenance（ NEm） was estimated as the antilog of the intercept of the linear regression between MEI and log10 HP. NE for weight gain（ NEg） was estimated based on the total body energy（ BE） and body weight（ BW） of ducks of the ad libitum group at different ages. The result showed as follows： there were significant differences of AME of diets,average daily feed intake（ ADFI）,average daily gain（ ADG）,feed to gain（ F / G）,body fat content,body protein content,body water content,body energy content,energy retained as fat（ REf）,energy retained as protein（ REp）,MEI,body energy retention（ RE）,and HP at different feeding levels（ P 〈0.05）. AME of diets,F / G,body protein content and body water content of restriction groups were significantly higher than those of the ad libitum group（ P 〈0. 05）; while ADFI,ADG,body fat content,body energy content,REf,REp,MEI,RE and HP of restriction groups were significantly lower than those of the ad libitum group（ P 〈0.05）.The regression equation between MEI and log10 HP of ducks aged from 2 to 3 weeks was： log10 HP = 2. 76 ＋0.000 1 ×MEI,and regression equation between BE and BW was： BE =- 768.87 ＋ 10. 71 ×BW. It is concluded that the NEmof Tianfu meat ducks aged from 2 to 3 weeks is 577. 03 k J /（ kg BW0.75·d）,and the NEgis10.71 k J / g,therefore,the NE requirement of Tianfu meat ducks aged from 2 to 3 weeks can be calculated by the following formula： NE = 577. 03BW0.75＋ 10. 71 △W.