Department of Pathology, College of Veterinary Science and A.H., DUVASU, Mathura-281001 (UP)
Online published on 19 December, 2013.
For this study 40 female goats were procured from an organized farm and divided into three groups comprising 10 goats (Sham-immunized) in group I, 15 goats (Indigenous vaccine) in group II and 15 goats (Gudair vaccine) in group III. The period of study was 450 days. All the groups were challenged twice with 3X109 MAP Bison type (strain S5) on 50 DPV and with 5X109 MAP Bison type (strain S5) on 270 DPV. The goats of group II & III gained higher body weight as compared to sham-immunized goats (group I). There was no significant difference in body weight gain observed in between the vaccinated groups.
The four control animals (group I) sacrificed at 200 DPV showed emaciation and depletion of body fat and mild to moderate lesions of focal/diffuse thickening of small intestine with or without corrugations specifically at ileocaecal junction characterized by mild to moderate catarrhal enteritis with infiltration of mononuclear cells and epitheloid cells. The remaining goats sacrificed at 450 DPV showed thickening of small intestine with chronic catarrhal enteritis and shortening, thin, atrophied and ballooned villi with infiltration of mononuclear cells and epitheloid cells, which at places fused to form giant cells. In vaccinated groups II & III, sacrificed at 200 DPV very few lesions but there were focal thickening of intestines in 5 cases each at 450 DPV with lesions of chronic catarrhal enteritis adorned with presence of lymphocytic, plasma cells and macrophages with a few epitheloid cells. MLN collected from group I at 200 DPV sacrificed goat revealed presence of oedematous fluid and focal infiltration of mononuclear cells with scattered presence of epitheloid cells and few giant cells and on 450 DPV showed mosaic like arrangement of epitheloid cells with presence of multinucleated giant cell. In vaccinated groups (II & III), at 450 DPV only, the MLN showed infiltration of MNC and a few epitheloid cells. The study of body score at 200 and 450 DPV on the parameters of body conformation, carcass components fat measurements revealed better marks in vaccinated animals (groups II & III) than control (group I). These parameters in both the vaccinated groups did not differ significantly.
The Cell mediated immune response revealed the impact of both vaccinated and experimental infection by MAP S5 strain on the proliferation of PBMCs. The CMI response (SI value) increased at 30 DPV and showed down regulation from 90 DPV and onwards in vaccinated goats (group II & III) and control goats (group I) which was higher in the vaccinated groups. The studies on humoral immune response at 180 DPV showed significantly increase in vaccinated goats and maintained till 450 DPV. Highest peak was recorded at 360 DPV in vaccinated animals while at 450 DPV in sham-immunized goats. Microscopic examination of fecal samples showed at 180 DPV, 5 animals of control group started showing positive results onwards till experimentation and MAP shedding increased with progression of time, while at 400 DPV one goat of each vaccinated group was found to shed bacilli (MAP) which were very few in number. Culture of fecal samples showed growth on HEY medium with mycobactin J confirmed the goats as positive for JD only in group I at 200 DPV. In the DNA samples, IS 900 PCR was applied in all the goats of each group revealed 100% (4/4), 11.9% (1/9) & 11.9% (1/9) positivity for MAP DNA in animals of group I, II & III at 360 DPV, respectively.
