不同填饲量对北京鸭胴体品质、体脂沉积和营养物质表观消化率的影响

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300g.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、480g.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390.7g.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。

Effects of Force-feeding Levels on Carcass Quality, Body Fat Deposition and Apparent Digestibility of Nutrients for Pekin Ducks

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·d-1 at 35 d of age and increased to 300 g·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·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 percentage(LMP)were observed among treatments(P>0.05).Breast muscle weight(BMW) increased with increasing feeding level from the control group to 390 g·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·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 overfeeding 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.