Immunopotentiation of a developed Salmonella enterica serotype enteritidis vaccine by thymulin and zinc in meat chicken breeders

The humoral immunity, spleen and thymus weight indices, lymphocyte count in the thymus cortex, and granuloma diameter at vaccination sites were assessed in four differently immunopotentiated groups of meat chicken breeders. Breeders in the first two groups were given a killed Salmonella enterica serotype Enteritidis (SE) vaccine subcutaneously at 15 and 19 weeks of age. Breeders in the third and fourth groups were left unvaccinated. Breeders in the first group were further immunopotentiated with zinc and thymulin. Each bird in the first group was given the immunopotentiators intraperitoneally in a volume of 0.1 ml at intervals of 3 days for a period of 3 weeks, starting at 15 weeks of age. At each time, each bird in the first group received thymulin (10 ng) and ZnCl2 (1 micromol/L), using a carboxymethyl cellulose carrier, totalling 90 ng thymulin and 9 micromol of ZnCl2 per bird. Each bird in the first three groups was challenged orally with 6.7 x 10(6) cfu/ml of highly virulent SE organisms, at an age of 22 weeks. The first group, which had received zinc and thymulin, had the earliest and highest humoral immune response to SE (p<0.05). This was observed at 2 and 4 weeks after the first vaccination. In addition, the first group had the highest mean thymus weight index, and the highest mean lymphocyte count in the thymus cortex. No significant difference was observed between the first two vaccinated groups in the mean granuloma diameter developed at the two vaccination sites 48 h after administration of the vaccine (p>0.05).

Induction of early immunopotentiation to Fimbriae of Salmonella Enteritidis (SE) by administering thymulin and zinc to SE-vaccinated chicken breeders: relationship to protection

The purpose of this study is to attempt the induction of early immunopotentiation of antibodies specific to fimbriae of Salmonella enterica serovar Enteritidis (SE), by administering thymulin and zinc to SE-vaccinated chicken breeders, and the improvement of protection against a controlled-live challenge by SE. The first two groups of breeders were administered subcutaneously at 15 and 19 weeks of age a killed SE vaccine. Breeders of the third and fourth groups were left unvaccinated. Breeders of the first group, immunopotentiated by thymulin and zinc, were able to induce the earliest antibodies in their pooled sera at 2 weeks post the first SE-vaccination, specific to fimbriae (approximately 21 KDa) of SE. However, the second group that was only vaccinated with the same SE-vaccine produced specific antibodies to fimbriae at 3 weeks following the second vaccination (22 weeks of age). Breeders of the third group, that were neither SE-vaccinated nor immunopotentiated by thymulin and zinc, but were challenged by live SE at 22 weeks of age, were able to show specific antibodies to fimbriae at 3 weeks post challenge (25 weeks of age). The fourth group that was deprived of SE-vaccination, immunopotentiators, and challenge didn't show any background antibodies specific to SE-fimbriae. The presence of the earliest antibody-immunopotentiation to fimbriae of SE in breeders of the first group, administered thymulin and zinc, was associated with the lowest frequency of SE-infected ceca (10%) among the challenged groups. In addition, breeders of the first group were the only challenged birds resulting in absence of SE infection in their cecal tonsils. The first group-vaccinated, immunopotentiated, and challenged, and the second group-vaccinated and challenged only resulted in breeders with absence of SE infection in their oviducts and spleens. In conclusion, immunopotentiation of chicken breeders by thymulin and zinc induces the earliest specific antibodies to fimbriae of SE associated with the lowest frequency of SE-infected ceca, and absence of SE infection from cecal tonsils, oviducts and spleens.