Fouad A M, Zhang H X, Chen W, Xia W G, Ruan D, Wang S, Zheng C T
Institute of Animal Science, Guangdong Academy of Agricultural Science, Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, State Key Laboratory of Livestock and Poultry Breeding, Guangdong Public Laboratory of Animal Breeding and Nutrition, Guangdong Key Laboratory of Animal Breeding and Nutrition, Guangzhou 510640, China.
Department of Animal Production, Faculty of Agriculture, Cairo University, Giza 12613, Egypt.
Asian-Australas J Anim Sci. 2017 Feb;30(2):206-210. doi: 10.5713/ajas.16.0235. Epub 2016 Jun 9.
A study was conducted to test six threonine (Thr) levels (0.39%, 0.44%, 0.49%, 0.54%, 0.59%, and 0.64%) to estimate the optimal dietary Thr requirements for Longyan laying ducks from 17 to 45 wk of age.
Nine hundred Longyan ducks aged 17 wk were assigned randomly to the six dietary treatments, where each treatment comprised six replicate pens with 25 ducks per pen.
Increasing the Thr level enhanced egg production, egg weight, egg mass, and the feed conversion ratio (FCR) (linearly or quadratically; p<0.05). The Haugh unit score, yolk color, albumen height, and the weight, percentage, thickness, and breaking strength of the eggshell did not response to increases in the Thr levels, but the albumen weight and its proportion increased significantly (p<0.05), whereas the yolk weight and its proportion decreased significantly as the Thr levels increased.
According to a regression model, the optimal Thr requirement for egg production, egg mass, and FCR in Longyan ducks is 0.57%, while 0.58% is the optimal level for egg weight from 17 to 45 wk of age.
进行一项研究以测试六种苏氨酸（Thr）水平（0.39%、0.44%、0.49%、0.54%、0.59%和0.64%），以估算17至45周龄龙岩蛋鸭的最佳日粮苏氨酸需求量。
将900只17周龄的龙岩鸭随机分配到六种日粮处理组中，每个处理组包括六个重复栏，每栏25只鸭。
提高苏氨酸水平可提高产蛋量、蛋重、蛋质量和饲料转化率（呈线性或二次曲线关系；p<0.05）。哈夫单位评分、蛋黄颜色、蛋白高度以及蛋壳的重量、百分比、厚度和破裂强度对苏氨酸水平的提高没有反应，但蛋白重量及其比例显著增加（p<0.05），而随着苏氨酸水平的提高，蛋黄重量及其比例显著下降。
根据回归模型，龙岩鸭产蛋量、蛋质量和饲料转化率的最佳苏氨酸需求量为0.57%，而17至45周龄蛋重的最佳水平为0.58%。
