Determining the IgG concentrations in bovine colostrum and calf sera with a novel enzymatic assay

作     者：M.Drikic C.Windeyer S.Olsen Y.Fu L.Doepel J.De Buck 

作者机构：Department Production Animal HealthFaculty of Veterinary MedicineUniversity of Calgary 

出 版 物：《Journal of Animal Science and Biotechnology》 (畜牧与生物技术杂志（英文版）)

年 卷 期：2019年第10卷第1期

页      面：239-247页

核心收录：

学科分类：0710[理学-生物学] 0831[工学-生物医学工程（可授工学、理学、医学学位）] 0832[工学-食品科学与工程（可授工学、农学学位）] 1004[医学-公共卫生与预防医学(可授医学、理学学位)] 0905[农学-畜牧学] 09[农学] 0906[农学-兽医学] 0703[理学-化学] 0836[工学-生物工程] 

基　　金：Natural Sciences and Engineering Research Council of Canada Discovery Grant to JDB 

主　　题：Cattle Colostrum Immunoglobulins Passive immunity Radial immunodiffusion Split trehalase 

摘      要：Background: Immune protection in newborn calves relies on a combination of the timing,volume and quality of colostrum consumed by the calf after birth.Poor quality colostrum with inadequate immunoglobulin concentration contributes to failed transfer of passive immunity in calves,leading to higher calf morbidity and mortality.Therefore,estimating colostrum quality and ensuring the transfer of passive immunity on farm is of critical importance.Currently,there are no on-farm tools that directly measure immunoglobulin content in colostrum or serum.The aim of this study was to apply a novel molecular assay,split trehalase immunoglobulin G assay(STIGA),to directly estimate immunoglobulin content in dairy and beef colostrum and calf sera,and to examine its potential to be developed as on-farm test.The STIGA is based on a split version of trehalase TreA,an enzyme that converts trehalose into glucose,enabling the use of a common glucometer for signal detection.In a first study,60 dairy and64 beef colostrum and 83 dairy and 84 beef calf sera samples were tested with STIGA,and the resulting glucose production was measured and compared with radial immunodiffusion,the standard method for measuring immunoglobulin concentrations.Results: Pearson correlation coefficients between the methods were determined and the sensitivity,specificity,and accuracy of the test were calculated for different colostrum quality and failed transfer of passive immunity cut-off points.The correlations of the STIGA measured by colorimetric enzymatic reaction compared to radial immunodiffusion for dairy and beef colostrum were 0.72 and 0.73,respectively,whereas the correlations for dairy and beef sera were 0.9 and 0.85,respectively.Next,STIGA was tested in a blinded study with fresh colostrum and serum samples where the correlation coefficient was 0.93 and 0.94,respectively.Furthermore,the performance of STIGA followed by glucometer readings resulted in correlations with radial immunodiffusion of 0.7 and 0.85 for dairy and beef colostrum and 0.94 and 0.83 for dairy and beef calf serum.Conclusions: A split TreA assay was validated for measurement of the immunoglobulin content of colostrum and calf sera using both a lab-based format and in a more user-friendly format compatible with on-farm testing.