The Effect of Vaccination with Anticoccidial Vaccine on Cellular and Humoral Immunity in Chicken

The present work was performed to study the effect of vaccination with Cocci Vac B on cellular and humoral immunity of chickens. The study comprised 70 chicks hatched from hens none vaccinated against coccidiosis. The chicks were subdivided into 4 groups. The 1st group comprised 25 chicks, kept as apparently healthy control, the 2nd group consists of 10 chicks, infected with 10000 mixed sporulated Eimeria oocysts at 4 weeks old, the 3rd group comprised 25 chicks, vaccinated once with Cocci Vac B at one day old and the 4th group consists of 10 chicks vaccinated once with Cocci Vac B at one day old then challanged at 4 weeks old. Chicks in all groups were weighted weekly and feed consumption was calculated for each group during the experimental period (6 weeks). The cellular and humoral immune responses in addition to histopathological examination were studied. Infected chickens (group 2) showed a highly significant decease in body weight, weight gain, gain % and feed consumption. In contrast the vaccinated chicks (group 3) and the infected of previously vaccinated chicks (group 4) have no marked significant changes in the body performance when compared with healthy control. Regarding the cellular immune response, infected chicks of the 2nd group and vaccinated chicks of the 3rd group have nearly the same stimulatory effect on lymphocytic transformation rate, phagocytosis percent, bacterial killing percent and chemotaxis index. But vaccinated and infected ones of the 4th group showed marked stimulation when compared with healthy control. The leukogram of the 2nd, 3rd and 4th groups revealed significant increase in total leucocytic, heterophilic, lymphocytic, monocytic and eosinophilic counts when compared with healthy control. The humoral immune response revealed a highly significant increase in antibody titre of the 2 nd and 4 th groups compared with the healthy control. Serum IgM showed a significant increase in the 2 nd , 3 rd and 4 th groups. While IgG showed a significant increase in 3 rd and 4 th groups compared with health control. These results were confirmed by histopathological examination of the intestine and bursa which revealed severe reaction in response to infection of the 2 nd group. On other hand the reaction was mild in the 3 rd and moderate in the 4 th group. From our study we recommended that: Vaccination against coccidiosis is cost effective, compared with the anticoccidial program , and it came over the problems of chemical residues in poultry meat, which happened due to the use of anitcoccidial drugs as food additives in prophylactic