Estimation of lysine requirement for growing-finishing pigs using a precision feeding technique | 采用精准饲养技术评估生长育肥猪的赖氨酸需要量

صينى. 目的通过测定日粮赖氨酸水平对生长育肥猪生长性能和体蛋白沉积的影响，评定生长育肥猪个体赖氨酸的日需要量，为精准饲养营养需要量的估计和应用奠定基础。方法按每日赖氨酸维持需要为0.036×BW0.75，蛋白质的需要量为体增重的16%（其中，赖氨酸的需要量为7%，日粮可消化赖氨酸存留率为72%）计算生长育肥猪赖氨酸预期日需要量，以该需要量的60%―110%设计6个赖氨酸水平组；（28 ± 2.2）kg的生长猪和（68±5.8）kg的育肥猪各60头，每个群体随机分为6个处理，每个处理10头，试验期28 d。智能精准饲喂器将配制的4种预混日粮以不同比例混合，得到每头猪每日相应赖氨酸水平的日粮。结果当生长育肥猪日粮赖氨酸供给量由预期日需要量的60%增加至110%时，日增重、蛋白沉积及饲料转化率呈增加趋势，且生长猪的日增重、蛋白沉积及饲料转化率在赖氨酸供给量达需要量的100%时出现平台阶段。赖氨酸摄入量差值分析发现，当生长猪和育肥猪赖氨酸的供给量达预期日需要量的110%时，赖氨酸摄入量差值最接近于0。精准饲养与传统三阶段饲养相比，25―55 kg生长猪氮、磷的摄入量及排泄量分别减少13%和35%以上；68―100 kg育肥猪氮、磷的摄入量及排泄量分别减少约10%和20%。结论在体重25―55 kg生长阶段，精准评估每头猪只每天的赖氨酸需要量方法准确；而对体重68―100 kg的实验猪，该方法可能低估了赖氨酸需要量。此外，精准饲养可以显著降低氮、磷的摄入量和排泄量。

إنجليزي. Objective An experiment was conducted to investigate the effects of dietary lysine concentration on performance and body composition by precision feeding technique in growing-finishing pigs. Method Daily lysine requirements were calculated assuming that maintenance requirements are of 0.036×BW0.75, that 16% of the body weight gain is protein, that 7 % of the body protein is lysine, and that the efficiency for lysine retention from dietary apparently digestible lysine is of 72%. The 6 lysine levels were generated by feeding pigs with 60%-110% of the calculated requirements of the control pigs. Performance trials with 60 growing pigs at (28 ± 2.2) kg and 60 finishing pigs at (68 ± 5.8) kg were conducted in a duration of 28 d, respectively. Six dietary treatments were assigned randomly to 60 pigs. Four premixes were mixed in the adequate proportions to obtain the appropriate concentration of lysine all over the experiment by the automatic and intelligent precision feeder. Result Average daily gain, protein deposition and feed conversion increased linearly with the increasing lysine provided in relation to requirement (from 60 to 110%) in both periods, and a plateau appeared after the 100% lysine requirement for growing pigs. The residues lysine intakes were closed to 0 when the provided lysine reached 110% of the requirement. Compared to the traditional three-phase feeding system, feeding pigs from 25-55 kg with daily tailored diets reduced N and P intake both by 13%, and the corresponding excretions were reduced both by over 35%. Feeding pigs from 68-100 kg with daily tailored diets reduced N and P intake both by 10%, and the corresponding excretions were reduced both by nearly 20%. Conclusion The method proposed in this study is appropriated in estimating the daily lysine requirement for individual pigs at the liveweight of 25 to 55 kg, but maybe underestimated the daily lysine requirement at the liveweight of 68 to 100 kg. It was improved that the precision feeding is an essential method to reduce the nutrient and phosphorus intake and excretion.