EVALUATION OF NEWCASTLE DISEASE VIRUS MATERNALLY DERIVED ANTIBODIES IN QUAIL CHICKS FOR ESTIMATION OF PROPER VACCINATION TIME

Abstract

The present study was conducted to monitor the persistence of Maternal Derived Antibody (MDA) in quail chicks during first five weeks of their life and its effect on the immune response to Newcastle disease virus vaccination (LaSota and Hitchner B1).The obtained results showed that, the MDA HI titers ranged from 5 to 7 (log2) with a geometric mean of 6.2 - 6.4 (log2) at the end of first week. At the end of the second week of age (day 14) the MDA HI titers were decreased with a mean titer of 5.1 - 5.2 (log2). At the end of the third week, only 40% of quail chicks (4/10) showed titers more than 5 (log2), whereas 60% of the quail chicks titers less than 4(log2) in HI test. One week later (day 28), all of the quail chicks showed titers less than 4 (log2) in HI test. At the end of the fifth week, (day 35), the mean titer was decreased to its minimum level equal to (≤ 2.0 log2). The obtained results revealed that, the mean value of HI antibody titers declined in the first two weeks post vaccination with (LaSota and Hitchner B1) when vaccination take place at 7 day old, whereas higher and persistence antibody response takes place when vaccination applied at 14 or 21 day old. The findings of our study suggest that the 14th day of age is recommended as the proper time to start the first vaccination against ND in flocks of quail chicks with maternal antibodies.