The Effects of Threonine on Performance Parameters, Carcass Traits, Visceral Organ Indices and Serum Biochemical Parameters of Linwu Ducks, Aged 4 to 8 Weeks

ABSTRACT This study was conducted to establish dietary threonine (Thr) levels for Linwu ducks, aged 4 to 8 wk. Experimental diets formulated to contain 0.56, 0.61, 0.66, 0.71, 0.76, and 0.81% Thr fed to Linwu ducks. A total of 360 healthy Linwu female ducks with similar body weight (1183.89±3.83 g) were randomly divided into six groups, with five replicates in each group, and 12 ducks in each replicate. Samples were collected at 8 wk for the determination of growth performance, carcass traits, visceral organ indices, and serum biochemical parameters. As a result of this study, Thr level had no significant influence on the final weight, the daily gain, feed/gain ratio, and average daily intake (p>0.05). Similarly, there were no significant effects of dietary Thr on carcass traits and visceral organ indices (p>0.05). The pancreatic index was highest among all the treatments when the dietary Thr level was 0.66%. The different dietary Thr levels had no significant effect (p>0.05) on the concentration of total protein (TP), triglyceride (TG), total cholesterol (TC), glucose (GLU), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and glutathione (GSH). However, the serum MDA concentration in the 0.66% treatment was lower (P=0.068) than in the other treatments. In conclusion, Thr at 0.66% concentration may have an antioxidant activity and exert positive effect on Linwu ducks.

摘要 本研究旨在确定4至8周龄临武鸭的日粮苏氨酸（threonine, Thr）适宜水平。试验配制了苏氨酸水平分别为0.56%、0.61%、0.66%、0.71%、0.76%和0.81%的日粮用于饲喂临武鸭。选取360只体重相近（1183.89±3.83 g）的健康雌性临武鸭，随机分为6组，每组设5个重复，每个重复12只鸭子。于8周龄时采集样本，测定生长性能、屠宰性状、内脏器官指数及血清生化指标。研究结果显示，日粮苏氨酸水平对临武鸭的末重、日增重、料重比及平均日采食量均无显著影响（p>0.05）。同样，日粮苏氨酸水平对屠宰性状和内脏器官指数亦无显著影响（p>0.05）。当日粮苏氨酸水平为0.66%时，试验组的胰腺指数达到最高。不同日粮苏氨酸水平对血清总蛋白（total protein, TP）、甘油三酯（triglyceride, TG）、总胆固醇（total cholesterol, TC）、葡萄糖（glucose, GLU）、超氧化物歧化酶（superoxide dismutase, SOD）、丙二醛（malondialdehyde, MDA）、谷胱甘肽过氧化物酶（glutathione peroxidase, GSH-Px）及谷胱甘肽（glutathione, GSH）的浓度均无显著影响（p>0.05）。但0.66%苏氨酸组的血清丙二醛浓度较其余各组更低（P=0.068）。综上，日粮中添加0.66%的苏氨酸可能具有抗氧化活性，并对临武鸭产生积极作用。