本文旨在用强饲-排空法研究肉鸭植物性饲料原料有效磷的可加性。选择体重相近的21日龄樱桃谷雄性肉鸭84只，随机分为7组，每组6个重复，每个重复2只鸭。分别强饲70 g玉米、豆粕、棉籽粕、菜籽粕和等比例混合的玉米-豆粕、玉米-豆粕-棉籽粕、玉米-豆粕-棉籽粕-菜籽粕混合饲粮，集粪袋法收集48 h排泄物，测定磷的生物学效价。结果显示，肉鸭对3种组合混合饲粮中，玉米-豆粕-棉籽粕组合的总磷表观利用率、总磷真利用率、表观有效磷和真有效磷的实测值与计算值差异显著（P<0.05），玉米-豆粕和玉米-豆粕-棉籽粕-菜籽粕2种混合饲粮实测值与计算值差异不显著（P>0.05）。由此得出如下结论：1）饲料原料真有效磷的可加性优于表观有效磷的可加性；2）不同饲料原料可加性优劣因原料组合不同而存在一定的差异。

This study was executed to research the evaluation and additivity of available phosphorus (P) in feedstuffs of plant origin for ducks with emptying-force-feeding method. Eight-four 21-day-old ducks with similar weight and excreta-collecting apparatus were randomly assigned into 7 treatments with 6 replicates in each treatment and 2 ducks in each replicate. The ducks under trial were starved for 72 h. After fasting period, the ducks from different treatments were fed by gavage with 70 g corn, soybean meal, cottonseed meal, rapeseed meal or their equal proportion mixtures, which included corn-soybean, corn-soybean-cottonseed, and corn-soybean-cottonseed. Excreta was collected separately for 48 h and bioavailability of P was evaluated. The results showed that for mixed diets corn-soybean-cottonseed, there was significant difference between analyzed and calculated values for the apparent phosphorus availability, true phosphorus availability, apparent available phosphorus and true available phosphorus (P<0.05), while there was no significant difference between the other two mixed diets (P>0.05). It was concluded that, 1) the additivity of true available phosphorus was better than that of apparent phosphorus for different feedstuffs of plant origin; 2) the additivity of apparent available phosphorus and true available phosphorus were variable for different combination of feedstuffs. ［Chinese Journal of Animal Nutrition, 2010，22（4）:917-922］