Immune response of chicken to an experimental sonicated coccidia oocyst vaccine

A total of 120 one-day old broiler chicks (Ross breed) were used to evaluate the humoral immune response of vaccine-I (supernatent from sonicated sporulated oocyst), vaccine-II (sediment from sonicated sporulated oocysts) and vaccine-III (un-sonicated sporulated oocyst) against coccidiosis in chicks was determined by indirect haemagglutination (IHA) test. IHA antibody titre was significantly higher (p0. 05) in chicks vaccinated with vaccine-I as compare to vaccine-II and vaccine-III. The IHA antibody titre of chicks vaccinated with vaccine-I ranged from 1:7 to 1:7012, 1:16 to 1:410 for vaccine II and 1:2 to 1:64 for vaccine III. Vaccine I gave 100 percent protection and oocysts appeared in the faeces (100-200 oocysts per grams) on day 11 post challenge which gradually number of oocysts creased, 650 to 900 oocysts per grams on day 17 and 200-400 on day 21 post challenge. Vaccine-II gave 62 percent protection and oocyst appeared in the faeces (300,000-400,000 oocysts) on day9 post challenge which gradually increased (800,000-900,000 oocysts) on day 17 and 100,000-200,000 on day 21post challenge. Vaccine III gave 33 percent protection and oocyst appeared in the faeces (800,000-900,000) on day 8 post challenge which gradually increased (100,000-1,250,000 per grams) on day 17 and 840,000 -900,000 on day 21 post challenge. In control group, characteristic bloody diarrhoea was observed in all the chicks and oocysts appeared in the faeces (1,000,000-1,250,000 per grams) on day 6 post challenge of faeces which gradually increased (1,400,000-1,750,000 per grams) on day 17 post challenge. the overall findings of this study indicate that the humoral and challenge response of the Vaccine I indicated a strong protection as immune chicks contained high level of antibodies that resisted heavy dose of challenge and gave 100 percent protection.