The interactive effects of dietary energy levels and genetic selection of intramuscular fat content on growth performance of Beijing-You chicken | 日粮能量水平与肌内脂肪遗传选择对北京油鸡生产性能的互作影响

Chinese. 本试验旨在研究不同日粮代谢能水平对肌内脂肪（intramuscular fat,IMF）双向选择系北京油鸡生产性能和胴体性状的影响。采用4（日粮代谢能水平）×2（IMF上、下选系）两因子设计。选择3周龄体重为（163±0.23）g的北京油鸡上、下选系公鸡各240只,各系随机分为4组,分别饲喂代谢能为12.122MJ.kg-1（ME1）、12.540MJ.kg-1（ME2）、12.958MJ.kg-1（ME3）和13.376MJ.kg-1（ME4）的4种日粮,每个处理组5个重复,每个重复12只鸡。13周龄屠宰。结果显示：（1）随日粮能量水平提高,日增重显著增加（P〈0.05）,料肉比显著下降（P〈0.05）,活重、屠体重、净膛重、胸肌重和腿肌重显著增加（P〈0.05）,而IMF选择对生产性能和胴体性能影响不显著（P〉0.05）,上选系的日采食量和活重显著高于下选系（P〈0.05）,日粮能量水平和IMF选择对胸肌重、腿肌重及其相对比率有显著交互作用（P〈0.05）。（2）随日粮能量水平提高,胸肌和腿肌IMF显著提高,在ME3组达到最大,ME4组下降（P〈0.05）,而腹脂重和腹脂率显著增加（P〈0.05）。上选系胸肌和腿肌IMF、腹脂重和腹脂率显著高于下选系（P〈0.05）,血浆总胆固醇显著低于下选系（P〈0.05）。日粮能量水平和IMF双向选择的互作对腹脂重、腹脂率和总胆固醇有显著影响（P〈0.05）。提高日粮能量水平可以显著提高油鸡生产性能,但不能补偿遗传选择形成的IMF含量差异,进一步证实通过遗传选择可以有效提高IMF含量。[著者文摘]

English. The experiment was conducted to study the effects of different dietary metabolism energy （ME） levels on performance and carcass composition in Beijing-You chicken divergently selected for intramuscular fat. Two factors and eight treatments were designed in this experiment. Four ME levels （12. 122, 12. 540, 12. 958 and 13.376 MJ・ kg. 1） × 2 strains （Up-selected and Down-selected lines, UL or DL） were included ,480 male chickens with 5 replicates of 12 birds each. The birds were fed with the designed diets from 21 d to 91 d of age and with 70 days of trial period. The results showed that ADG, LW, CW, EW, BMW and TMW were elevated but FCR was reduced significantly （P 〈 0. 05 ） with dietary ME levels increased. Significant effect of IMF selection was observed on performance and carcass composition of experimental birds, ADFI and LW of UL were significantly higher than those of DL （P 〈 0. 05）. IMF selection and dietary ME levels showed significant interaction on BMW, TMW, BMR and T MR. The IMF content of breast and thigh muscle reached their peaks at ME3, but the AFW and AFR were constantly in proportion to dietary ME concentrations. The birds of DL exhibited lower IMF, AFW and AFR than those of UL, with the reverse for TC （ P 〈 0. 05 ）. In addition, the marked interactive influence of dietary ME levels and IMF selection on AFW, AFR and TC was also observed （P 〈 0. 05）. Increasing dietary ME levels could improve growth performance of Beijing-You chicken. However, genetic results of IMF selection couldn＇t be modified by changing the dietary energy level. Moreover, the availability of genetic selection on IMF contents in chickens was identified.