Comparative Study On The Immune Efficacy Of Vaccine Against Porcine Circovirus Virus Disease

Porcine circovirus disease caused by Porcine circovirus type2(PCV-2), mainlyincluding Postweaning multisystemic wasting syndrome(PMWS) and Porcine dermatis andnephropathy syndrome(PDNS).When swine infected PCV-2, The body’s immune functionwas damaged,it can lead to the swine’s immunosuppression which could increase thepathogenicity of coinfecting agents.The bring economic losses cannot be ignored in swineindustry.Since PCV-2vaccine in foreign market from2007,it has become the importantmethod to prevent PCV-2infection. PCV-2vaccine was first extension use in China in2010,but part of farming enterprises was poor to know about vaccine immune effect and noreport about completed field experences of PCV-2vaccine.So we select kinds ofcommercializae PCV-2vaccine to evaluate of immune effects,which is practicalsignificance. The purpose of the study include:1、 To realize that changes of sowsproduction performance and their piglets maternal antibody levels after vaccination PCV-2vaccine.2、To study different commercializae PCV-2vaccines influence with swineimmune,swine immune performance and production performance,in addition searchrational immunization procedure of PCV-2vaccine. This study includes the followingsections.Test one: change observation of sows production performance and their piglets maternalantibody levels after vaccination PCV-2vaccine.The test is in one Hefei farm.640productive sows were vaccinated PCV-2Evaccine,and randomly select Childbirth in the same period,4parity multiparous sows andtheir5piglets.Collcet production data of sows vaccination around1years,including littersize, number born alive,number born death, Nest mummy tire in number,Nest produced a weak litter size, birth weight and estrus returning rate; in the prenatal oneweek,test sows were got the blood from anterior vena cava and separate blood serum,detectPCV-2antibody.Piglets respectively at before breastfeeding,10d,20d,30d,40d,50d and60d, were got the blood from anterior vena cava and separate blood serum,detect PCV-2antibody and nucleic acid.The results showed that after inoculation litter size and litter litter size could increaseby0.36and0.43respectively it was significant difference with that of before inoculation(p<0.01); weak litter size decreased by0.11it was significant difference with that of beforeinoculation (p<0.05); after sucking colostrum, antibody level in piglet levels at10days oldis higher than that of the other, and rapidly decreased until30day age, then materal antibodies decreased gradually with the increase of day age, moreover there was no PCV2could be detected in these piglets. This study showed that inoculated of PCV2vaccines cansignificantly improve sows performance and reduce piglet PCV2infection, to piglets thebest immunization period for PCV2should be at20day age.Test two: comparision test kinds of Porcine circovirus vaccine immune effectsIn the experiment,80selected10days healthy pigles randomly divide into4groups(A,B,C,D). At14days, piglets were reccpted first vaccination,at35days, secondvaccination,group C no need second vaccination.At20d,30d,40d,50d,60d,80d and110d,extract respectively from each group5piglets to get blood by vena cava anterior,separateserum.Dectect PCV-2antidody and nucleic acids by ELISA and PCR. Collect eachgroup pigs statistics including the average daily gain, feed conversion ratio and of deathand rate in conservation stage, growth stage and the fattening stage.The results shows that,group C average antibody level between20d and40d is higherthan other groups,the level is0.782at40d.it has significant difference between other threegroups, piglets day age that detected PCV-2nucleic acids is later than other groups.At growth fattening stage,the average daily gain of C group test pigs is0.788kg, feedconversion ratio is2.73and Superior To Others, Compared with groupA,groupB and groupD,the average daily gain of1.29%,12.09%and11.14%, respectively.feed conversion ratio reduce0.06,0.11,0.14,than others. Piglets survival rate of Group Creach100%,has no dead scouring pigs.But mortality and elimination rate of group A,groupBand group D is16.67%,11.11%,14.29%. So immune permanceand production performance analysis shows that the immunevaccine C is better.Test three: Immune procedure optimization of three kinds of PCV-2vaccineTest collected11010d healthy piglets randomly divid into11groups,was calledA1-4,B1-4,C1-2,D.A1and B1grooup carry on first vaccination at14d,second vaccinationat28d;A2and B2group were first vaccination at14d,second vaccination at35d;A3and B3group were first vaccination at21d,second vaccination at35d; A4and B4group were firstvaccination at21d,second vaccination at42d;C1and C2group were first vaccination at14d and21d respectively, no need second vaccination;D group is blank control.At20d,30d,40d,50dand60d, extract respectively from each group5piglets to get blood byvena cava anterior,separate serum.Dectect PCV-2antidody and nucleic acids by ELISA andPCR. Collection each group of pigs average daily gain and mortality and eliminationrate statistics, respectively.The results shows that,1、the average antibody level of group A4remarkable higher than group A3at40d(p<0.05), at60d the average antibody level of A3and A4group were1.005and0.909,which was remarkable higher than A1and A2（p<0.05）,moreover A4was not dected PCV-2nucleic acids;The average daily gain of A4was superior to others.2、At30d,the average antibody level of B3and B4were1.053and0.994,respectively,whichwas remarked higher than other three groups(p<0.05);At40d,the average antibody level ofB4was remarkable higher than B3(P<0.05);The average antibody level of B4was1.584at60d,which was notable superior to other four groups(P<0.05);So the average daily gain ofB3and B4marked higher than other groups(P<0.05).3、At30d and60d,the averageantibody level of C2were1.135and0.527,which was remarkable higher than C1andcontol group(P<0.05);The difference of average daily gian was not notable between C1and C2(P>0.05),nor detect PCV-2nucleic acids,the survival rate is both100%.4、In the21dfirst-immune group, at30d and60d the average antibody level were1.037and0.985,whichwas remarkable higher than the14d first-immune group(P<0.05);At40d and60d,theaverage antibody level of the interval21d booster immune group were notable superior tothe interval14d booster immune group and control group(P<0.05).consequently,immuneperformance and production performance analysis shows that vaccine the immune time ofA and B were first-immune at21d and second immune at42d. the first-immune At21d,immune effects of vaccine C was better.