This experiment was conducted to determine the effects of different force-feeding amounts on growth performance, serum biochemical parameters and liver histology of Pekin ducks. Ninety-six 35-day-old healthy male Pekin ducks with similar body weight were randomly assigned into 8 groups with 6 replicates per group and 2 Pekin ducks per replicate. The experimental feeding period lasted for 7 d from 35 to 42 days of age and the corn-soybean diets were provided to ducks in the 8 groups. The control group was fed ad libitum with average daily intake of (259. 55 ±18. 59) g and the other groups were fed by force-feeding. The feed intake of seven force-feeding groups in the first 2 days was the same which was 260 g/bird at 35 days of age and 300 g/bird at 36 days of age, and then the amount of feed provided to the ducks in each group remained unchanging during the other 5 days which was 300, 330, 360, 390, 420, 450 and 480 g/d for a bird, respectively. The results showed as follows; 1) the final average body weight and average daily gain (ADG) were significantly higher in the force-feeding groups except for 300 g/d force-feeding group than those in the control group (P <0. 05). The final average body weight and ADG were increased with the increasing of force-feeding amount, and when the amount was above 420 g/d, there was no significant difference (P >0. 05). The feed/gain (F/G) was no significantly different between each force-feeding group and the control group (P > 0. 05). Based on the broken-line regression model analysis with ADG data, the optimum force-feeding amount for Pekin ducks was 414. 2 g/d. 2) No significant differences in serum glucose (Glu) concentration, gluta-mate oxaloacetate transaminase (GOT) activity were observed among groups (P >0. 05). Serum 7-glutamyl-transferase (GGT) activity was significantly higher in 450 g/d force-feeding group than that in the control group, while there was no significant difference between the other force-feeding groups and the control group (P >0.05). Serum triglycerides (TG) , cholesterol (CHO) concentration and glutamate pyruvate transaminase (GPT) activity were significantly increased with the increasing of force-feeding amount (P <0. 05). Histology observation showed that the swelling of hepatocyte was observed and the cytoplasm was full of fat in several force-feeding groups compared to the control group. In conclusion, force-feeding to Pekin ducks can induce a strong fat deposition in liver tissue, but the growth performance is changeless when the feeding level is above 420 g/d.%本试验旨在研究不同填饲量对北京鸭生长性能、血清生化指标及肝脏组织学的影响.试验选取96只35日龄健康、体重相近的雄性北京鸭,随机分成8个组,每组6个重复,每个重复2只鸭,试验期为7d.对照组试鸭自由采食,平均日采食量为(259.55±18.59)g,填饲组试鸭在35日龄和36日龄时分别填饲260和300 g/d的玉米-豆粕型饲粮,之后5d各填饲组填饲量保持不变,分别为300、330、360、390、420、450、480 g/d.结果表明:1)除300 g/d填饲组外,其他填饲组北京鸭试验末重和平均日增重显著高于对照组(P＜0.05).试验末重和平均日增重随填饲量的提高而逐渐提高,当填饲量为420 g/d以上时,试验末重和平均日增重基本保持稳定(P＞0.05).填饲组料重比与对照组相比差异不显著(P＞0.05).以平均日增重为评定指标,采用直线折线模型进行估算的最适填饲量为414.2 g/d.2)不同填饲量对北京鸭血清葡萄糖浓度、血清谷草转氨酶活性没有显著影响(P＞0.05),450g/d填饲组血清γ-谷氨酰基转移酶活性显著高于对照组(P＜0.05),其他填饲组与对照组相比差异不显著(P＞0.05).血清甘油三酯、总胆固醇浓度和谷丙转氨酶活性随填饲量的提高而逐渐升高,且差异显著(P＜0.05).3)填饲使得北京鸭肝脏细胞肿大,胞浆中充满大量大小不等的脂肪滴.由此可见,填饲能够快速增加北京鸭的脂肪沉积,但填饲量超过420g/d时,北京鸭生长性能基本保持稳定.
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