National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Thirty thousand commercial broiler chicks in 30 different flocks were vaccinated with live attenuated lentogenic strain ND vaccine (local isolate) through drinking water at the age of day 5 and boostered on day 26 in field condition. Serum samples were collected randomly from 10% of the vaccinated chicks before primary vaccination, before boostering and before marketing. HI antibody titre was determined from each sample as per the method OIE, 2009. Twelve birds just before marketing (at the age of 40th day) of each 30 flocks were subdivided into two groups i.e. experimental group and vaccinated control group. Each experimental group (consists of 6 birds) was challenged with velogenic pathotype of NDV intra-nasally at the dose rate of 106 EID50 per bird at the age of 42nd day and another group (consists of 6 birds) was kept as vaccinated control. Both the groups of birds were reared for next 3 weeks and recorded for any mortality/ abnormality. Serum samples were collected from all the birds at the age of 42nd day (before challenge of the experimental group), 49th, 56th and 63rd day of age for detection of HI antibody titre. The overall mean HI antibody titres were 1.53805±0.03, 2.04491±0.04 and 2.27366±0.05 just before primary vaccination, before boostering and before marketing respectively. The overall mean antibody titre decreased significantly (1% level) on the 7th day post- challenge and then increased gradually in the survived birds on the 14th day post-challenge with 4.44% mortality and reached to peak level (2.4075±0.08) on the 21st day post-challenge in the experimental group. But in the vaccinated control groups the overall mean antibody titre gradually decreased with the advancement of age and dropped below protective level on the 63rd day of age with no mortality/abnormality.
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