Study On The Preparative Of Anti-Enterotoxigenic Escherichia Coli IgY Microcapsule And Valuation Effect Of Slow-Releasing

Weaned piglets often suffer from postweaning diarrhone(PWD)by Enterotoxigenic Escherichia Coli(ETEC),which cause impaired growth performance and high mortality.Piglets were infected with enterotoxigenic Escherichia coli rate about 40%in pathogens of PWD,which harmful to the piglets.This study exploit the anti-ETEC IgY Chitosan-Sodium Alginate microcapsule.The micrecapsule will be took orally and resorption by intestine,which can prevent and treat the PWD by ETEC.Study 1:A mixture of culture of K88,K99 and 987P Enterotoxigenic Escherichia Coli mixed with oil emulsion adjuvant, propolis adjuvant,aluminum hydroxide Al(OH)₃ adjuvant respectively. The laying hens were divided into 6 groups,which immunized three kinds vaccine of ETEC in two different kind of time Program.One, interva time is 14d among the first,the second and the third vacciation, the other is 30d.The result showed that the laying hens were immunized oil emulsion adjuvant of ETEC and the interval time 30d of vaccination was better,which obtain higher IgY activity and maintain the longer time. Collecting eggs with higher IgY activity,and crude IgY was separated from the yolks and purification with three kinds of methods:Water Diluting Method,Chloroform Method,and Caprylic-acid-Ammonium Sulfate Medthod.To compare with the three purification methods of IgY from yorks,Water Diluting Method was better,which for protein recovery and concentration,IgY activity.And the Water Diluting Method presents a more cost-effective,and convenient.Study2:Based on the study 1,preparation the an-ti ETEC IgY Chitosan-Sodium Alginate microcapsule.First,sellected the better coating terms of stability:the roundness of microcapsule,and the swelling rate under gastroinstestinal in vitro,which design the orthogonal tset L₉(4³).The best preparative conditions were:the dose of mixture molecular weight Chitosan and Sodium Alginate were 0.2-0.4%and 2-3%,the concention of calcium chloride(CaCl₂)were 1-3%,reaction pH and time were 4-6,15min.The drying temperature and time were 37℃, 3h.Second,beded the IgY into the ACS microcapsule,and test the highest beded concentration is 75%by protein concentration and IgY activity of core.Study 3:A gastroinstestinal in vitro experiment was carried out,to verify the stability of IgY ACS mircrocapsule,and to evalue the feasibility of coating processing procedure.This study showed:IgY in ACS mircrocapsule is protected in simulated gastric fluid(3h),and released rate is 90%in simulated intestinal fluid within 6h,which is well slow-release effect of dissolving in intestines.At the same time IgY ACS mircrocapsule stored at the room tempeture within 12 months,and protein concentration and IgY activity assay was carried out.The result showed that within 12 months the protein concentration and IgY activity were protected well.