饲料中蛋白质检测方案(定氮仪)

APPLICATIONNOTEF&F-D-006-2013/A1 N/PROTEIN DETERMINATION IN FEED N/Protein Determination in Feedaccording to Dumas combustion method Reference： AOAC 990.03 Protein (Crude) in Animal Feed Combustion Method Tested with VELP Scientifica NDA 701 Dumas Nitrogen Analyzer (Code F30800070) DUMAS COMBUSTION METHOD Introduction Protein is a critical nutrient in cattle， pig，poultry，sheep， horse and pet foods. Although protein supplements are high cost they are sometimes necessary in order to meet the animal’s nutritionalrequirements. An adequate protein content in feed products is important for animal health and productivity， as well as forranch profitability. The protein requirements of cattle vary with age， size， and expected performance. During lactation， larger cattle typically require more pounds of crude protein per day than smaller animals， but as a lowerpercentage of their total dry matter intake. In other words， lighter cattle require higher quality feeds and forages at lowerquantities compared with heavier cattle. Cattle requirements for crude protein rise with increasing lactation and rate ofgain. Protein is required for milk production and reproductive tract reconditioning after calving. . Protein Determination in Feed The Dumas method starts with a combustion furnace (CF) to burn thesample， obtaining elemental compounds. Water is removed by a first physical trap (WT1-DriStepTM)， placed afterthe combustion， and a second chemical one (WT2). Between the two， theelemental substances passed through a reduction furnace (RF). The auto-regenerative CO2 adsorbers (CO2) let pass only the elementalnitrogen that is detected by the LoGas TM innovative Thermal ConductivityDetector (TCD) with no requirement for a reference gas. The NDA 701 is controlled via PC through the intuitive DUMASoftTM. NDA 701 Preliminary Operations (daily) Follow the operating manual to start the NDA 701 and check that the following parameters are set： Temperature Combustion reactor (Code A00000158)：980°C Temperature Reduction reactor (Code A00000226)：580°C Flow rate MFC1 He： 190 ml/min Flow rate MFC2 He： 200 ml/min Condition the system by testing 2 EDTA standard (Code A00000149) and 3 to 5 empty tin foils (Code A00000153) asCheck up. Verify the calibration curve with one or more tests as Standard by testing the same standard used for the curve creation. Sample Preparation Grind the test samples using a grinder to suitable fineness (particle size ≤ 0.5 mm) to obtain ≤2，0 % relative standarddeviation (RSD) for 10 successive nitrogen determinations. Using a spatula， put the sample directly into the tin foil. Close the tin foil， obtaining a capsulee. Load the capsule into the autosampler. Analysis Procedure Fill the following fields in the database： Sample name， Weight， Method， Sample type， Calibration number The“FEED FOR ANIMALS， DRY"method shows the following parameters： Protein factor： 6.25 O2 flow rate：400 ml/min 02factor： 1.6 ml/mg The “SOYA BEAN" method shows the following parameters：Protein factor： 5.70O2 flow rate： 400 ml/minO2 factor： 1.8 ml/mg Press to start the analysis. Analysis time： from 3 minutes for one run. Samples： Animal's feed products： Indicative protein content： 1- Poultry ration 18.0% 30.0% 3-Dog food， dry 2- Pork feed24.0% 4- Fish feed， wet 45.8% 5- Soy meal 38.0 % Typical Results on Feed Products The results are calculated as a percentage of nitrogen and percentage of protein. Sample Sample quantity (mg) Nitrogen% Protein % Poultry Ration 103.2 2.863 17.894 102.1 2.884 18.025 100.1 2.898 18.111 Average ± SD% 2.882±0.018 18.010±0.109 RSD%* 0.611 0.607 Pork Feed 101.00 4.830 30.185 96.10 4.817 30.108 99.90 4.823 30.142 Average± SD% 4.823±0.007 30.145±0.039 RSD% * 0.135 0.128 Dog Food， Dry 99.90 3.883 24.266 99.60 3.805 23.780 102.70 3.843 24.021 Average±SD% 3.844±0.039 24.022±0.243 RSD%* 1.015 1.012 Fish Feed， Wet 50.20 7.378 46.110 50.50 7.341 45.880 47.60 7.312 45.700 Average ± SD% 7.344±0.033 45.897±0.206 RSD%* 0.450 0.448 Soy Meal 99.40 6.072 37.949 99.20 6.026 37.664 98.70 6.122 38.265 Average± SD% 6.073±0.048 37.959±0.301 RSD%* 0.791 0.792 Protein Factors： 6，25 for feeds and 5，70 for soy meal Protein Factors： 6，25 for feeds and 5，70 for soy meal*RSD%= (Standard Deviation * 100)/ Average Conclusion Theobtained results are reliable and in accordance with the expected value.The combustion method， relying on the Dumas principle， for the determination of total nitrogen in different kind of feeds，has been included as an official alternative to the Kjeldahl method. Results have been obtained with the following calibration curve： in a range of 0 -9 mg N with 5 measurements of EDTAstandard (%N=9，57) (Code A00000149). Benefits of Dumas combustion method are： e High productivity， non-stop performance ● Time saving， few minutes required Moderate running costs ● Totally unsupervised， fully automated Omission of harsh and toxic chemicals Eco-friendly， low amount of residues and wastes Several organizations workingg with standardization andrecommendation of chemicallmethodsihhaveaapprovedcombustion methods for the determination of nitrogen. Thanks to development in sophisticated instrumentation， the Dumas principle， became a practical and popularalternative for the determination of nitrogen in organic matrices. Copyright C VELP Scientifica. All rights reserved.No part of this publication may be reproduced or transmitted in any form or for any purpose without the express permission of VELP.VELP Scientifica， Italy Tel： + Fax： + www.velp.com 利用VELP NDA701杜马斯技术分析饲料中的蛋白质含量: 蛋白质是牛，猪，家禽，绵羊，马和宠物食品中的重要营养素。尽管蛋白质补充剂价格昂贵，但有时为了满足动物的营养需求，它们还是必需的。饲料产品中足够的蛋白质含量对动物健康和生产力以及牧场盈利能力至关重要。牛的蛋白质需求随年龄，大小和预期性能而变化。泌乳期间，大型牛通常比小型动物每天需要更多的粗蛋白，但占它们总干物质摄入量的百分比较低。 换句话说，与较重的牛相比，较轻的牛需要较少数量的高质量饲料和饲料。牛对粗蛋白的需求随着泌乳和增重率的增加而增加。 产犊后乳汁生产和生殖道修复需要蛋白质。