Evaluation of the levels of maternal immunity transferredto broilers in different ages of PS flock following vaccination against Avian Influenza subtype H9N2

The most common Avian Influenzasubtypein majority of involved flocks in Iran is H9N2, which is not included HPAIsubtypes. So with an appropriate biosecurity planning and a proper vaccination program, the subsequent losswill possibly come to naught.In the present study, it is tried to peruse the transferredAvian Influenzamaternal immunity levels from PS flockto the progeny and examine the role of this maternal immunity as the frontline strong defensive barrier of the progenyat the early age against Avian Influenza.The blood sampling procedure in this study is divided to two separate phases:1- Sampling from PS flock in the production period in 39, 44, 49, 54, 59 and 64 weeks of age.2- Sampling from day old chicks originated from the above mentioned PS flock at the aforesaid ages.By start of production, sampling from 8 houses in production period was done (20 birds per house). Each samplingroundleaded to 160 blood samples.After 21 days of each sampling round, the blood sampling was done from 160 appropriate quality day old chicks and sent to laboratory for HI test.The results show thatthe mean titers in PS flock was 8.5, 8.43, 8.4, 8.39, 8.24, 8.20at the age of 39, 44, 49,54, 59, 64 weeks respectively. Moreover, the mean titers in progeny originated from PS flock at the age of 39, 44, 49, 54, 59, 64 weeks was 5.36, 5.33, 5.2, 5, 4.95, 4.88 respectively. The percentage of maternal immunity levels which was transferred to progeny was 63.05%, 63.22%, 61.90%, 59.59%, 60.07%, 59.51%at the age of 39, 44, 49, 54, 59, 64 weeks respectively.Normally, the mean titer levels decrease by age increasing in PS flock. Moreover, it was determined that there is a reduction in maternal immunity transfer potency by age increasing based on percentage of transferred maternal immunity in this study.The reduction of mean titer levels in PS flock and potency of maternal immunity transfer continued until the end of the production period such that around week 39, the percentage of maternal immunity was 63%, but at the late production period at week 64, it decreased to below than 60% in the progeny.Subsequently, the mean titer levels in progenydecreased continuously as age increasing of PS flock.

Keywords:

Maternal Immunity Transfer , Progeny , Avian Influenza , HI , Vaccination