不同方法测定肉鸭内源磷排泄量的比较研究

A Comparison of Different Methods to Measure the Endogenous Phosphorus Output in Meat Ducks

本研究通过比较无磷饲粮法、梯度回归法和差量法测定肉鸭内源磷排泄量的差异,旨在确立合理的肉鸭内源磷排泄量测定方法。选取21日龄雄性樱桃谷肉鸭150只,随机分成5个处理,每个处理设6个重复,每个重复5只鸭。采用无磷原料配制无磷纯合饲粮,以豆粕为唯一含磷原料配制总磷水平分别为0.20%、0.35%、0.51%和0.55%的低磷梯度饲粮。试验饲粮中均添加0.4%二氧化钛（TiO2）作为外源指示剂。试验肉鸭21~24日龄采食全价颗粒饲料,25~30日龄采食相应的试验饲粮,并按重复准确记录采食量。收集28~30日龄期间全部排泄物,风干,测定磷和TiO2含量,计算内源磷排泄量。结果显示,饲粮磷水平在0.20%~0.55%范围内,饲粮磷摄入量与粪磷排泄量之间存在显著的线性关系（P〈0.05）,内源磷的排泄量基本稳定。无磷饲粮法、梯度回归法和差量法测得的肉鸭内源磷排泄量分别为1.20、0.37和0.29 g/kg DM。I由此得出,梯度回归法和差量法测得的肉鸭内源磷排泄量基本一致,这2种方法都是可行的;而采用无磷饲粮法测定肉鸭内源磷排泄量存在较大误差。

In order to establish a reasonable method to measure the endogenous phosphorus output in meat ducks,P-free method,regression analysis method and difference method were used to measure the endogenous phosphorus output in meat ducks.One hundred and fifty 21-day-old healthy male cherry valley ducks were randomly assigned into 5 treatments with 6 replicates per treatment and 5 ducks per replicate.P-free pure diet was formulated with P-free feedstuffs.Soybean meal was used as the only source of phosphorus to formulate 4 P-low gradient diets containing different levels of phosphorus（0.20%,0.35%,0.51% or 0.55%） based on corn starch.Titanium dioxide（TiO2） with the supplemental level of 0.4% was added to experimental diets as exogenous marker.During 21-to 24-day-old,all ducks were fed with complete pellet feed.During 25-to 30-day-old,ducks were fed with experimental diets and the feed intake recorded by replicate.The excreta were collected by replicate from 28-to 30-day-old.All samples were air-dried,and total phosphorus and TiO2 contents were measured.Endogenous phosphorus output was calculated.The results showed that there was no significant linear relationship between dietary phosphorus input and fecal phosphorus output（P0.05）,and the endogenous phosphorus output remained relatively stable.The endogenous phosphorus output in meat ducks was 1.20,0.37 and 0.29 g/kg DMI,respectively,when measured by P-free method,regression analysis method and difference method.In conclusion,the endogenous phosphorus output in meat ducks can be measured by both regression analysis method and difference method,but a larger error was caused by P-free method.