This experiment was conducted to determine the effects of different force-feeding levels on carcass quality, body fat deposition and apparent digestibility of nutrients for Pekin ducks. Ninety-six 35-day-old health male Pekin ducks with similar pen weight were randomly assigned into 8 treatments with 6 replicates per treatment and 2 Pekin ducks per replicate. Apparent digestibility of nutrients was determined with chromic oxide (Cr2O3) at an inclusion rate of 0. 5% in basal diet. The experimental feeding period lasted 7 d from 35 to 42 d of age and the corn-soybean diet was fed to the eight groups of ducks, the control group by ad libitum-feeding and the experimental groups by force-feeding. The force-fed intake was 260 g o d-1 at 35 d of age and increased to 300 g o d-1 at 36 d of age. The force-fed intake unchanged during the other five days and they were 300,330,360,390,420,450 and 480 g o d-1 each treatments, respectively. The results showed as follows; ( 1) No significant differences in dressing percentage(DP) , eviscerated percentage(EP),breast muscle percentage(BMP) ,leg muscle weight(LMW) and leg muscle per- centage(LMP) were observed among treatments (P＞0. 05). Breast muscle weight ( BMW) increased with increasing feeding level from the control group to 390 g o d-1 (P＜0. 05＝ and then decreased (P＞0. 05). Based on the broken-line regression model analysis with BMW data, the optimum feeding levels for force-feeding Pekin ducks was 390. 7 g o d-1 ; These were significant differences among treatments in body fat deposition index(P＜0. 05＝. But body fat deposition were unchange when force-feeding levels reached a certain value (P＞0. 05). (2)For the final o-verfeeding period, there were significant differences in apparent digestibility of dry matter and crude protein (P＜0. 05＝, whereas apparent digestibility of energy had no significant differences (P＞0. 05) between different treatments. In conclusion, overfeeding of Pekin ducks can induces a strong fattening of subcutaneous adipose tissues and muscles and force-feeding has a significant effect on breast muscle growth. However, nutrients digestibility decrease and body fat deposition keep unchange with increasing force-feeding levels.%旨在研究不同填饲量对北京鸭胴体品质、体脂沉积及营养物质表观消化率的影响.选取35日龄健康、大小均匀的W系雄性北京鸭96只,随机分成8个处理,每处理6个重复,每个重复2只鸭.基础日粮中加入0.5％的Cr2O3作为外源指示剂测定填鸭营养物质表观消化率,对照组自由采食,试验组在35和36日龄时分别填饲260和300 g·d-1的基础日粮,之后5d各处理填饲量保持不变,分别为300、330、360、390、420、450、480 g·d-1,试验期为7d.结果表明:(1)不同填饲量对北京鸭屠体率、全净膛率、胸肌率、腿肌质量和腿肌率影响不大(P＞0.05),而对北京鸭胸肌质量影响显著(P＜0.05),并随填饲量的增加呈现先升高后平稳的趋势,以胸肌质量为评定指标,采用直线折线模型进行估算的最适填饲量为390.7 g·d-1.不同填饲量对北京鸭皮脂质量、皮脂率、腹脂质量、腹脂率、肝脏质量、肝重率和肝脂率均有显著的影响(P＜0.05),但填饲量增加到一定值后,体脂沉积量保持稳定(P＞0.05)；(2)在填饲期,不同填饲量对北京鸭干物质和粗蛋白表观消化率影响显著(P＜0.05),而对能量表观消化率影响不大(P＞0.05).以上结果表明,填饲能够快速增加北京鸭的体脂沉积,对胸肌生长发育影响显著,但随填饲量的增加,营养物质表观消化率下降,填鸭体脂沉积量不再增加.
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