Efficacy of live vaccine (LCV-2) against coccidiosis for cage-reared and floor-reared chickens
YAN Hong-bin,TIAN Guang-fu,JIA Wan-zhong,JING Zhi-zhong,CAI Xue-peng(Key Laboratory of Veterinary Parasitology of Gansu Province,State Key Laboratory of Veterinary Etiological Biology,Lanzhou Veterinary Research Institute,Chinese Academy of Agricultural Sciences,Lanzhou 730046,China)
Two experiments were designed to test the efficacy of LCV-2,a coccidiosis vaccine for chickens.In experiment 1,the efficacy of LCV-2 was evaluated on male broilers,Chinese Yellow strain,reared in wire cages on the basis of relative ratio of weight gain,OPG(oocysts per gram of stool),morbidity and score of intestinal tract lesions and anticoccidio index(ACI) after violent challenge.Results showed that in vaccinated challenged groups,the maximum percentage protection(survivors after challenge) against mixed species of Eimeria were 100%,and relative ratio of weight gain was observed in vaccinated non-challenged group(97.74%),which was significantly higher(P0.05)than vaccinated challenged group(89.72%) and unvaccinated challenge group(69.85%).Furthermore,the difference between vaccinated challenged group and unvaccinated challenged group was significantly higher(P0.05).After challenge,the average OPG of unvaccinated challenged group(1.26×105) was significantly higher(P0.05)than vaccinated challenged groups(5.813×104),the average score of intestinal lesions were also record in unvaccined challenged groups followed by vaccined challenged groups and vaccined non-challenged group(1).The higher ACI were calculated in vaccinated non-challenged birds(192.74)and vaccinated challenged birds(178.76),which significantly higher than unvaccinated challenged birds(62.18).In experiment 2,the efficacy of LCV2 were evaluated in vaccinated challenged groups,negative control group and unvaccinated non-challenge group(which reared in one floor-pen with vaccinated challenge group together) on the basis of relative ratio of average weight gain,average OPG and intestinal lesions,too.Results showed that chickens of vaccinated non-challenged groups(with the relative ratio of weight gain 99.39%) grown faster than vaccinated challenged(with the relative ratio of weight gain 91.67%),but no significant difference was found from these two groups.After challenge,the intestinal lesions of vaccinated challenged group got worst,which score of intestinal lesions was 4,and followed by unvaccinated no-challenged group(with intestinal lesions score:1),and no intestinal lesions was observed in negative groups(with intestinal lesions score 0).Furthermore,the OPG of unvaccinated non-challenged group(3.675×105) was significantly lower(P0.05)than vaccinated challenged group(6.025×105) after challenge,and significantly lower(P0.01)before challenged too(7.5×104,3.5×104).The highest ACI was calculated in unvaccinated non-challenged birds(193.39),which followed by vaccinated challenged birds(175.76).From these results,it can be concluded that the vaccinated chickens,no matter of which reared in cages or in floorpens were resistant to coccidiosis with the floor-reared chickens vaccinated by LCV-2 to be better.
【Fund】： 国家高技术研究发展计划“863计划”资助项目(2006AA10A207);; 国家科技支撑计划资助项目(2007BAD40B00)
【CateGory Index】： S858.31
【CateGory Index】： S858.31