Development Of Yolk Powder Against Quadrivalent Pili Proteins For Prevention And Curing Piglet Diarrhea Caused By Escherichia Coli

Enterotoxigenic Escherichia Coli (ETEC) is the main pathogen of colibacillosis of neonatal and post weaned piglets. The pathogenesis of ETEC is strongly related to adhesive fimbriae and enterotoxin.Mechanisms in the pathogenesis of piglets diarrhea caused by ETEC is that ETEC attach to the small intestine by means of the adhesive fimbriae and replicate and elaborate enterotoxin that interfere the biochemistry of small intestine cell. To treat this disease, we usually use antibacterial medicine or antiserum, however it is restrained because of high cost and low production. So there are chances of developing a new kind of biological medicine instead of antibacterial drugs.In this study, two groups of hens 28-week old were immunized with mixed Escherichia Coli pili and mixed Escherichia Coli respectively. After contrasting the difference between two methods, we had the conclusion that the titers of the former were higher than these of the later.Especially the titers of K88 from pilia immunity was up to 29 which was two levers higher than that of bacterial immunity. On this basis,we chose mixed pili of Escherichia Coli to inject hens.After the third immunity,the titer of IgY had reached a high lever and this lever couLd last for about three months.And the result of spray drying of extracted IgY showed that 140℃entering and 72℃exiting were the most suitable conditions without changing the activity of IgY.In order to study the stability of IgY powder fartherly, we used temperature ladder,PH ladder, protease and the time length of conservation to be the outer conditions and ensured that this powder had good stability and such as acid resistance,alkali proof,enzyme proof and easy-conservation.According to the adhesion and adhesion-inhibition assay between ETEC and intestine epithelium,we know that after spray drying, the power of IgY couLd also inhibit effectively the adhesion.In the adhesion group,one cell can be adhered with 23.79 K88+ ETEC on average,otherwise ,in the adhesion-inhibition group,one cell couLd adhere 1.98 K88+ ETEC dealed with before-spray-drying IgY(P < 0.01),otherwise 1.23 dealed with after-spray- drying IgY(P < 0.01).So this assay confirmed that the egg-yolk powder after spray-drying actually has clinical value to prevent diarrhea of piglet.This study also provide science foundation for studying, developing and functioning this new compound strengthen egg powder to prevent and cure diarrhea of the neonatal piglet.