饲粮中代谢能和蛋氨酸水平对育肥期北京鸭生长性能、屠宰性能和血浆生化指标的影响

Effects of Dietary Metabolizable Energy and Methionine Levels on Growth Performance,Carcass Characteristics,and Plasma Biochemical Parameters for Growing Pekin Ducks

旨在研究饲粮代谢能(ME)和蛋氨酸(Met)水平对15~42日龄北京鸭生长性能、屠宰性能和血浆生化指标的影响,确定不同饲粮Met水平北京鸭的ME需要量。采用2×6双因子完全随机试验设计,选取576只15日龄体重相近[(545.9±3.3)g]的雄性北京鸭,随机分成12组,每组8个重复,每重复6只鸭;试验设置2个Met水平(0.30%、0.50%),6个饲粮ME水平(10.47、11.10、11.72、12.35、12.98、13.61 MJ·kg^(-1)),试验期28 d。结果表明:1)随着饲粮中ME水平的升高,42日龄北京鸭平均体重和15~42日龄平均日增重显著增加(P<0.05),平均日采食量和料重比显著降低(P<0.05)。2)随着饲粮中ME水平的升高,42日龄北京鸭胸肌率和腿肌率显著下降(P<0.05),全净膛率、腹脂率和皮脂率显著增加(P<0.05)。3)随着饲粮中ME水平的升高,42日龄北京鸭血浆中总胆固醇和高密度脂蛋白胆固醇含量显著降低(P<0.05),游离脂肪酸含量显著增加(P<0.05),白蛋白含量有下降的趋势(P=0.053);饲粮中Met水平升高可显著升高血浆中白蛋白含量(P<0.05)降低血浆游离脂肪酸含量(P<0.05);且饲粮中ME和Met水平对血浆中总胆固醇和高密度脂蛋白胆固醇含量存在显著的交互作用(P<0.05)。4)根据折线模型,以日增重为评价指标,饲粮Met水平为0.30%和0.50%时,满足北京鸭最佳日增重的ME需要量分别为12.46和12.85 MJ·k^(g-1);经过t检验,饲粮Met水平为0.50%时北京鸭的ME需要量有高于Met水平为0.30%时的趋势(0.10<P<0.05)。综上所述,饲粮中能量水平升高改善北京鸭生长性能,饲粮中Met水平影响北京鸭ME需要量。

This experiment was conducted to investigate the effects of dietary methionine(Met)and metabolizable energy(ME)levels on growth performance,carcass characteristics,and plasma biochemical parameters of Pekin ducks from 15 to 42 days of age,and to determine the ME requirements of Pekin ducks at different dietary Met levels.A 2×6 two-way completely randomized experimental design was used,and 576 male Pekin ducks,with similar weight[(545.9±3.3)g]at 15 days of age,were randomly divided into 12 groups with 8 replicates per group and 6 ducks per replicate.The present experiment was set with 2 Met levels(0.30%,0.50%)and 6 dietary ME levels(10.47,11.10,11.72,12.35,12.98,and 13.61 MJ·kg^(-1)).The experiment was lasted for 28 days.The results were showed as follows:1)As dietary ME levels increased,the average body weight at 42 days of age and the average daily weight gain of Pekin ducks from 15 to 42 days of age were significantly increased(P<0.05),average daily feed intake and feed to gain ratio decreased significantly(P<0.05).2)As dietary ME levels increased,the percentage of breast meat and leg meat were decreased significantly(P<0.05),the percentage of slaughter eviscerated carcass,abdominal fat,and sebum subcutaneous fat were significantly increased(P<0.05).3)With the increasing dietary ME levels,the plasma total cholesterol and high density lipoprotein cholesterol contents of Pekin ducks at 42 days of age were significantly decreased(P<0.05),while the free fatty acid content was significantly increased(P<0.05),and the albumin content had a tendency to decrease(P=0.053).Dietary Met supplementation significantly increased plasma albumin and reduced free fatty acid contents(P<0.05),and there exists a significant interaction effect between dietary ME and Met levels on plasma total cholesterol and high density lipoprotein cholesterol contents(P<0.05).4)Based on the linear broken line model,the ME requirements to meet the optimal average daily weight gain of Pekin ducks were 12.46 and 12.85 MJ·kg^(-1) at dietary 0.30%and 0.50%Met levels,respectively.The t test showed that the ME requirements of Pekin ducks at dietary 0.50%Met level tended to be greater than those at 0.30%Met level(0.10<P<0.05).Taken together,increasing dietary energy level can improve the growth performance of Pekin ducks,and dietary Met level could affect dietary ME requirement of Pekin ducks.